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THE  CUPOLA  FURNACE: 


A  PRACTICAL  TREATISE  ON  THE 


CONSTRUCTION  AND  MANAGEMENT 


FOUNDRY  CUPOLAS. 


COMPRISING 

THE  BEST  METHODS  OF  CONSTRUCTION  AND  MANAGEMENT  OF  CUPOLAS;  DIFFERENT 

SHAPED  CUPOLAS;  HEIGHT  OF  CUPOLAS;  PLACING  TUYERES;  SHAPES  OF  TUYERES; 

LINING;  SPARK  CATCHING  DEVICES;  BLOWERS;  BLAST  PIPES;  AIR  GAUGES; 

CHARGING;  DIRECTIONS  FOR  THE  MELTING  OF  IRON,  TIN-PLATE  SCRAP, 

AND  OTHER  METALS  IN  CUPOLAS;  EXPERIMENTS  IN  MELTING; 

WHAT  A  CUPOLA  WILL  MELT;  ETC. 


BY 

EDWARD  £IRK. 

PRACTICAL  MOULDER  AND  MELTER,  CONSULTING  EXPERT  IN  MELTING. 
Author  of  The  Founding  of  Metals,  and  of  Numerous  Papers  on  Cupola  Practict 


ILLUSTRATED    BY   SEVENTY-EIGHT    ENGRAVINGS. 


PHILADELPHIA  : 
HENRY  CAREY  BAIRD  &  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTER 
Sio  WALNUT  STREET. 

LONDON : 
E.  &  F.  N/SPON,  LTD., 

125    STRAND. 


COPYRIGHT,  1899, 

BY 
EDWARD  KIRK. 


PRINTED  BY  THE 
WICKERSHAM   PRINTING  COMPANY, 

53  and  55  North  Queen  Street, 
LANCASTER,  PA.,  U.  S.  A. 


PREFACE. 


ALTHOUGH  it  is  now  more  than  twenty  years  since  the  pub- 
lication of  the  author's  volume,  "  The  Founding  of  Metals," 
that  book  is  still  in  demand.  The  reception  which  has  been 
tendered  to  it,  together  with  the  urgent  requests  of  many 
foundrymen  for  a  more  modern  work  on  cupolas,  has  encour- 
aged him  to  prepare  the  treatise  now  offered  to  the  public. 

This  volume  is  designed  to  supply  a  want  long  felt,  for  a 
work  on  melting  that  would  give  practical  details  regarding 
the  construction  and  management  of  cupolas,  and  the  melting 
of  iron  for  foundry  work.  Several  valuable  books  have  been 
written  on  the  moulding  and  founding  of  iron  and  steel,  but  in 
these  books,  as  in  the  foundry,  but  comparatively  little  attention 
is  given  to  the  cupola ;  and  foundrymen  and  melters  have  been 
left  to  grope  very  much  in  the  dark,  and  to  rely  solely  on  their 
own  experience,  in  the  construction  and  management  of  their 
cupolas. 

This  condition  of  things,  and  the  great  importance  of  the 
subject,  have  combined  to  induce  the  author  in  the  present 
work  to  endeavor  to  develop  the  most  vital  principles  con- 
nected with  the  cupola,  its  construction  and  its  use,  together 
with  the  best  practice  of  this  country.  In  order  to  accomplish 
these  ends,  he  has  supplemented  his  almost  lifelong  experience 
by  consulting  the  latest  works  on  foundry  practice,  and  by 
visiting  leading  and  thoroughly  up-to-date  foundries  in  different 
parts  of  the  United  States.  He  therefore  trusts  that  this  book 
will  prove  to  be  a  useful  aid  to  foundrymen,  whether  owners  or 
workers,  both  here  and  abroad. 

(in) 


91403 


iv  PREFACE. 

As  is  the  general  custom  of  the  publishers,  they  have  caused 
the  work  to  be  supplied  with  a  copious  table  of  contents,  as 
well  as  a  very  full  index,  which  will  render  reference  to  any 
subject  in  it  both  prompt  and  easy. 

EDWARD  KIRK. 

PHILADELPHIA,  February  22,  1899. 


CONTENTS. 


CHAPTER  I. 
THE  CUPOLA  FURNACE. 

PAGE 

Advantages  of  the  cupola  furnace  for  foundry  work;  Quantity  of  fuel 
required  for  melting  iron  in  various  kinds  of  furnaces;  Attempts  to 
decrease  the  amount  of  fuel  consumed  in  the  cupola  by  utilizing  the 
waste  heat 1 

Description  of  the  cupola  furnace;  Forms  of  cupolas;  Sizes  of  cupolas; 
Foundation  of  a  large  cupola 2 

Advantage  of  iron  supports  over  brick-work;  Height  of  the  bottom  of 
the  cupola;  Pit  beneath  the  cupola 3 

Bottom  plate;  Bottom. doors;  Support  of  the  doors;  Various  devices  for 
holding  the  doors  in  place;  Construction  of  the  casings  ...  4 

Stack  casing;  Construction  of  the  stack;  Tuyere  holes    ....       5 

L/ocation  of  the  charging  door  and  its  construction;  Lining  of  the  casing 
and  materials  used  for  it 6 

The  scaffold  and  its  location;  Construction  of  the  scaffold;  Size  of  the 
scaffold i 

CHAPTER  II. 

CONSTRUCTING  A  CUPOLA. 

Proper  location  of  a  cupola;  The  scaffold  .         .         .        .         .         .         .       8 

Conveyance  of  coal  or  coke  to  the  scaffold;  Cupola  foundation  and  its 
construction  ............  9 

Prevention  of  uneven  settling;  Brick  walls  for  the  support  of  a  cupola; 
Best  supports  for  a  cupola  .........  10 

Height  of  cupola  bottom;  Provision  for  the  removal  of  the  dump;  Bot- 
tom doors.  ............  11 

Casing;  Material  for  the  casing  or  shell  of  the  modern  cupola  and  stack; 
Strain  upon  the  casing  due  to  expansion  and  shrinkage  and  its  pre- 
vention; Contraction  of  the  stack;  Prevention  of  sparks  .  .  .12 

What  constitutes  the  height  of  cupola;  Utilization  of  the  waste  heat; 
Table  giving  the  approximate  height  and  size  of  door  for  cupolas  of 
different  diameters  ...........  13 

Melting  capacity  of  a  cupola;  Charging  door;  Air  chamber     .         .         .14 

(v) 


VI  CONTENTS. 

PAGE 

Construction  of  the  air  chamber  when  placed  inside  the  casing  and  when 
placed  upon  the  outside  of  the  shell;  Air  capacity  of  the  air  chamber; 
Admittance  of  the  blast  to  the  air  chamber  ......  15 

Location  and  arrangement  of  the  air  chamber  when  the  tuyeres  are 
placed  high;  Tap-hole 16 

Arrangement  when  two  tap-holes  are  required;  The  spout  and  its  con- 
struction; Tapping  of  slag 17 

Location  of  the  slag-holes;  Tuyeres;  Number  of  tuyeres  for  small 
cupolas .18 

Best  shape  of  tuyere  for  a  small  cupola;  Number  of  tuyeres  for  large 
cupolas ;  Size  of  combined  tuyere  area ;  Tuyere  boxes  or  casings ; 
Height  at  which  tuyeres  are  placed  in  cupolas  .  .  .  .  .19 

Objection  to  high  tuyeres;  Two  or  more  rows  of  tuyeres;  Arrangement 
of  a  large  number  of  rows  .........  20 

Area  of  the  rows;  Increase  in  the  melting  capacity  with  two  or  three 
rows  of  tuyeres;  Lining;  Material  for  lining  the  casing  .  .  .21 

Grouting  or  mortar  for  laying  up  a  lining;  Manner  of  laying  the  brick; 
Thickness  of  cupola  linings;  Stack  lining  ......  22 

Arrangement  of  brackets 23 

Preference  by  many  of  angle  iron  to  brackets;  Mode  of  putting  in  angle 
iron;  Reduction  of  the  lining  by  burning  out  .  .  .  .  .24 

Settling  of  the  lining;  Mode  of  reducing  the  size  and  weight  of  the  bot- 
tom doors  and  preventing  the  casing  from  rusting  off  at  the  bottom; 
Prevention  of  the  absorption  of  moisture  into  the  lining  .  .  .25 

Illustration  of  the  triangular-shaped  tuyere  in  position  in  the  lining; 
Form  of  bottom  plates.  Fire-proof  scaffolds;  Exposure  of  the  scaf- 
fold and  its  supports  to  fire 26 

Devices  to  make  scaffolds  fire-proof;  Novel  plan  of  construction  of  a 
scaffold  and  cupola  house  in  Detroit,  Mich 27 

Best  and  safest  scaffolds;  Cupola  scaffold  in  the  foundry  of  Gould  & 
Eberhardt,  Newark,  N.  J.,  and  of  the  Straight  Line  Engine  Co.,  Syra- 
cuse, N.  Y 28 

CHAPTER  III. 

CUPOLA  TUYERES. 

Modes  of  supplying  the  cupola  furnace  with  air;  Admission  of  the  air 
through  tuyeres  or  tuyere  holes;  Former  and  present  melting  capacity 

of  a  cupola;  Epidemics  of  tuyere  invention 30 

The  round  tuyere;  Arrangement  of  round  tuyeres  in  the  old-fashioned 

cast-iron  stave  cupolas 31 

Oval  tuyere;  Expanded  tuyere  .........     32 

Doherty  tuyere     .         .         .         .         . 33 

Sheet  blast  tuyere;  Horizontal  slot  tuyere;  Mackenzie  tuyere.         .         .     34 
Blakeney  tuyere 35 


CONTENTS.  vii 


Horizontal  and  vertical  slot  tuyere  .  .36 

Reversed  T  tuyere  or  vertical  and  horizontal  slot  tuyere;  Vertical  slot 

tuyere;  Truesdale  reducing  tuyere.         .......    37 

Lawrence  reducing  tuyere  ..........     38 

Triangular  tuyere;  Results  in  melting  with  this  tuyere  obtained  by  the 

Magee  Furnace  Co.,  Boston,  Mass  .  .  - 39 

Water  tuyere 40 

Colliau  tuyere;  Whiting  tuyere  .........     41 

Chenney  tuyeres;  The  double  tuyere;  Mode  of  placing  the  tuyeres  in 

Ireland's  cupola;  Claims  for  the  double  tuyere  .....  42 
Consumption  of  fuel  in  a  double  tuyere  cupola;  Three  rows  of  tuyeres; 

Cupola  constructed  by  Abendroth  Bros.,  Port  Chester,  N.  Y.  .  .43 
Object  in  placing  tuyeres  in  a  cupola;  Production  of  heat  by  consuming 

the  escaping  gases  from  the  combustion  of  fuel     .         .         .         .         .44 

Greiner  tuyere;  Adjustable  tuyeres    ........     45 

Cupola  of  the  Pennsylvania  Diamond  Drill  and  Manufacturing  Co., 

Birdsboro,  Pa. ;  Bottom  tuyere        ........     46 

Mode  of  covering  the  mouth  of  a  bottom  tuyere        .         .         .         .         .47 

Bottom  tuyere  patented  in  this  country  by  B.  H.  Hibler;  Thomas  D. 

West  on  the  bottom  tuyere 48 

Size  of  tuyeres;  Size  of  the  combined  tuyere  area  of  a  cupola  .  .  .49 
Height  of  tuyere;  Great  difference  of  opinion  on  this  subject;  Experi- 
ments with  tuyeres  at  various  distances  above  the  sand  bottom  .  .  50 
Experiment  to  soften  hard  iron  by  bringing  the  molten  metal  in  contact 

with  charcoal  in  the  bottom  of  a  cupola;  Reason  given  in  favor  of  high 

tuyeres      .............     51 

Tuyeres  in  stove  foundry  cupolas;  Location  of  tuyeres  in  smaller  cupolas.  52 
Tuyeres  in  machine  and  jobbing  foundry  cupolas,  and  in  cupolas  for 

heavy  work       ............     53 

Number  of  tuyeres;  Objection  to  the  use  of  only  one  tuyere;  Two  tuyeres 

sufficient  for  the  largest  cupola  in  use     .......     54 

Arrangement  of  a  double  row  of  tuyeres;  Shape  of  tuyeres;  Tuyeres  to 

improve  the  quality  of  iron     .........     55 

Tuyere  boxes 56 

CHAPTER  IV. 

CUPOLA  MANAGEMENT. 

Necessity  of  learning  the  peculiarities  in  the  working  of  a  cupola;  A 
cupola  cannot  be  run  by  any  given  rule  or  set  of  rules;  Drying  the 
lining  .  .  .  .  .  .  .  .  .  .  .  .58 

Drying  a  backing  or  filling  between  the  casing  and  lining;  Putting  up 
the  doors;  Devices  for  raising  the  doors  into  place  .  .  .  .59 

Support  of  double  doors;  Sizes  of  props  to  support  the  bottom        .         .     60 


viii  CONTENTS. 


Ring  attachment  to  the  prop;  Superstition  of  older  melters  regarding 

the  prop;  Dropping  the  doors;  Modes  of  releasing  the  prop         .         .     61 
Sand  bottom;  Sand  employed  for  this  purpose;  Objection  to  clay  sands 

and  other  sands;  Sand  which  makes  the  very  best  kind  of  bottom       .     62 
Wetting  the  bottom  sand;  Bringing  the  sand  into  the  cupola  .         .         .63 

Cause  of  leakage  in  the  sand  bottom 64 

Boiling  of  iron  due  to  a  wet  bottom;  Pitch  or  slope  of  the  bottom  .         .     65 
Effect  of  a  high  pitch;  Change  in  the  action  of  the  iron  at  the  spout  by 

the  pitch  of  the  bottom;  How  the  bottom  should  be  made    .         .         .66 
Slope  of  the  bottom  in  cupolas  with  two  tap  holes;  Spout;  Spout  lining 
material     .............     67 

Effect  of  the  use  of  too  much  clay  or  of  too  much  sand  in  the  lining; 

Mode  of  making  up  the  spout  lining 68 

Building  up  the  sides  of  the  lining;  Place  of  the  greatest  strain  upon  the 
spout  lining      .............     69 

Proper  shape  of  the  spout  lining;  Cause  of  pools  of  iron  forming  in  the 

spout;  Removal  of  slag  from  the  spout 70 

Front;  Material  used  for  putting  in  the  front;  Mode  of  putting  in  the 

front 71 

Effect  of  working  the  front  material  too  wet;  Troubles  due  to  poor  front 
material    .............     72 

Sizes  of  tap  hole;  Locating  the  holes 73 

Slag  hole .74 

Slag  hole  front;  Chilling  of  slag  in  the  tap  hole       .....     75 
Lighting  up;  Mode  of  placing  the  wood  and  shavings  in  the  cupola; 

Putting  in  the  bed  fuel 76 

Effect  of  carelessness  in  arranging  the  wood  and  lighting  up  .         .         .77 
The  bed;  The  melting  point  in  a  cupola;  The  melting  zone  and  deter- 
mination of  its  exact  location;  Necessity  of  discovering  the  melting 

point  in  order  to  do  good  melting 77 

To  find  the  melting  point 78 

Cause  of  trouble  in  melting  after  a  cupola  has  been  newly  lined;  Fuel 
required  for  a  bed  in  cupolas  of  different  diameters       .         .         .         .79 

Charging;  Old  way  of  loading  or  putting  the  fuel  and  iron  into  a  cupola; 
Modern  way  of  stocking  a  cupola;  Correct  theory  of  melting  iron  in  a 
cupola       .............     80 

Practical  working  of  a  cupola  upon  this  theory  ;   Effect  of  too  heavy 
charges  of  iron,  and  of  too  heavy  charges  of  fuel;  Variation  in  the 

weight  of  the  first  charge  of  iron 81 

Variations  in  the  per  cent,  of  iron  to  fuel;  Placing  the  charges       .         .     82 
Mode  of  placing  the  pieces  of  pig  or  other  iron ;  Distribution  of  the 
charge  of  fuel;  Charging  additional  iron         ......     83 

Poor  melting  may  be  due  to  bad  charging;  Improper  and  proper  charg- 
ing of  a  cupola;  Charging  flux;  On  what  the  quantity  of  flux  depends    84 
Blast;  The  old  and  the  modern  ways  of  giving  blast  to  the  cupola;  Blast 
phenomena .85 


CONTENTS.  ix 


Melting;  When  melting  begins  in  a  cupola;  Difference  in  opinion  as  to 
the  time  for  charging  the  iron  before  the  blast  is  put  on  .  .86 

Best  time  for  putting  on  the  blast;  Chilling  and  hardening  of  the  first 
iron;  Running  of  a  heat  without  stopping  in;  Mode  of  reducing  the 
size  of  the  tap-hole  .  .  .  .  .  .  .  .  .  .  .  87 

No  advantage  in  holding  molten  iron  in  a  cupola  to  keep  it  hot;  Proper 
management  of  hand-ladle  work;  Indication  of  how  the  cupola  is 
melting  by  the  flow  of  iron  from  the  tap-hole  .  .  .  .  .  88 

Poking  the  tuyeres       ...........     89 

Fuel;  Amount  of  fuel  required  in  theory  and  in  practice;  Necessity  of 
keeping  an  accurate  account  of  the  amount  of  iron  melted  .  .  .  90 

Chief  object  of  melting  iron  in  a  cupola;  The  old  story  of  "  not  enough 
blast;"  Necessity  of  an  even  volume  of  blast.  .  .  .  .  .91 

Tapping  bars;  Shapes  and  sizes  of  tapping  bars 92 

Steel  bar  for  cutting  away  the  bod  before  tapping;  Bod  sticks;  Combin- 
ation stick 93 

Objection  to  the  combination  stick;  Number  of  bod  sticks  for  each 
cupola;  Bod  material;  Importance  of  the  material  of  which  the  bod  is 
composed.  ............  94 

Mixture  for  a  good  bod;  Bod  for  small  cupolas;  Qualities  of  a  good  bod.     95 

Tapping  and  stopping  in;  Mode  of  making  the  bod;  How  to  make  the 
tap 96 

Mode  of  stopping  in;  Difficulties  in  stopping  in;  Devices  to  assist  in 
stopping  in  ............  97 

The  skill  of  the  melter  seen  at  the  tap-hole;  Uneven  melting  is  the  fault 
of  the  melter;  Dumping ..........  98 

Removal  of  the  small  props;  Bridging  over  of  small  cupolas  above  the 
tuyeres  and  mode  of  removing  the  bridge 99 

Various  methods  of  handling"  the  dump;  Removing  the  dump  and  vari- 
ous devices  for  this  purpose  .........  100 

Breaking  up  the  dump  and  picking  it  over;  Different  ways  of  recovering 
the  iron  from  the  dump;  Chipping  out  .......  101 

Theory  of  some  melters  to  prevent  iron  from  running  into  the  tuyeres; 
Objection  to  this  theory;  Cupola  picks 102 

Daubing;  Materials  used 103 

Soaking  fire  clay;  Amount  of  sand  required  for  mixing  with  the  clay; 
No  advantage  in  using  a  poor  cheap  daubing 104 

Putting  on  the  daubing;  Shaping  the  lining;  Object  of  applying  daub- 
ing to  a  lining;  Mode  of  making  new  linings 105 

Chipping  off  cinder  and  slag  that  adhere  to  the  lining  over  the  tuyeres; 
Not  necessary  or  advisable  to  fill  in  the  lining  at  the  melting  zone; 
Objections  to  sudden  offsets  or  projections 106 

Thickness  of  the  daubing;  Sectional  view  of  a  cupola,  illustrating  effect 
.of  excessive  daubing 107 

Shaping  the  lining  of  the  boshed  cupola;  Special  directions  required  for 


X  CONTENTS. 

PACK 

shaping  and  keeping  up  the  lining  of  the  patent  and  odd-shaped 
cupolas 109 

Relining  and  repairing;  Thickness  of  the  lining;  Location  of  the  great- 
est wear  on  the  lining;  Destruction  of  the  lining  at  and  below  the  tuy- 
eres; Length  of  time  a  cupola  lining  will  last;  Burning  away  of  the 
lining  .............  110 

Thickness  of  lining  required  to  protect  the  casing;  Repairing  the  lining 
at  the  melting  zone Ill 

Repairing  a  lining  with  split  brick;  Mode  of  making  a  split  brick  .         .  112 

CHAPTER  V. 
EXPERIMENTS  IN  MELTING. 

Various  opinions  formerly  held  by  foundrymen  as  to  the  point  in  a 
cupola  at  which  the  melting  of  iron  actually  took  place;  Different  ways 
of  charging  or  loading  a  cupola       .........  113 

Experiments  to  learn  definitely  at  what  point  iron  is  really  melted  in  a 

cupola;  Construction  of  an  experimental  cupola 114 

Results  of  the  first  experiment   .         .         .         .         .         .         .         .         .115 

Arrangement  of  the  bars  of  iron  for  the  next  experiment         .         .         .  116 
What  was  learned  from  this  experiment;  Arrangement  of  the  bars  and 
cupola  for  the  next  heat  ..........  117 

High  pressure  of  blast  may  be  almost  wholly  due  to  the  size  of  the  tuy- 
eres; Arrangement  of  the  bars  for  the  next  heat  and  the  result  of  this 
experiment       .         .         .         .         .         .         .         .         .         .         .         .118 

Arrangement  of  the  cupola  for  the  next  heat  and  result  of  the  experi- 
ment   119 

Fuel  used  in  the  experiment;  Reasons  why  iron  is  not  melted  in  a  cupola 
by  the  blast  and  flame  of  the  fuel;  Melting  zone  in  a  cupola  .  .  120 

Fire  under  the  tuyeres        .         . 121 

Low  tuyeres;  Results  of  an  experiment  with  low  tuyeres.         .         .         .122 
Melting  zone;  What  determines  the  location  of  a  melting  zone  in  a 

cupola;  Lowering  and  raising  the  melting  zone 123 

Change  in  the  location  and  depth  of  the  melting  zone      ....  124 
Experiments  to  learn  the  depth  of  the  melting  zone  in  practical  melting.  125 

Charges  used  in  the  experiments 126 

Charges  with  which  the  most  melting  was  done  in  these  experiments; 
Necessity  of  passing  the  blast  through  a  certain  amount  of  heated  fuel 

before  a  melting  zone  was  formed  in  a  cupola 127 

Cause  of  iron  melted  high  in  a  cupola  being  made  dull    ....  128 
Development  of  the  melting  zone  above  the  tuyeres;  Experiments  with 

a  cupola  with  the  tuyeres  placed  near  the  top;  Failure  of  this  plan      .  129 
Melting  with  coal;  Softening  hard  iron;  Experiments  in  softening  iron 
by  passing  it  in  molten  state  through  charcoal  in  its  descent  from  the    ' 
melting  zone  to  the  bottom  of  the  cupola       .         .         .        .         .         .  130 


CONTENTS.  xi 


Time  for  charging;  Difference  of  opinion  among  foundrymen  as  to  the 
proper  time  for  charging;  Experiments  to  ascertain  the  proper  time 
for  charging  and  putting  on  the  blast  after  charging     ....  132 

Devices  for  raising  the  bottom  doors  ........  133 

Device  for  raising  heavy  doors   .         . 134 

CHAPTER  VI. 

FI.UXING  OF  IRON  IN  CUPOLAS. 

Definition  of  a  flux;  Use  of  fluxes;  Materials  used  as  fluxes;  Purpose  of 
the  use  of  limestone  in  the  production  of  pig-iron  ....  135 

On  what  the  making  of  a  brittle  cinder  in  a  cupola  by  the  use  of  lime- 
stone depends;  Limestone  in  large  quantities  .....  136 

Variation  in  the  quantity  of  limestone  required  to  produce  a  fluid  slag; 
Weight  of  slag  drawn  from  a  cupola  .  .  .  .  .  .  .137 

Constituents  of  the  slag;  Effect  of  flux  upon  iron     .....  138 

The  action  of  fluxes  on  lining    .........  139 

How  to  slag  a  cupola;  Cause  of  trouble  in  slagging;  General  method 
of  charging  the  limestone;  The  slag  hole 140 

Slag  in  the  bottom  of  a  cupola;  Importance  of  the  time  for  drawing  the 
slag;  Does  it  pay  to  slag  a  cupola?  Estimate  of  the  cost  of  slagging  .  141 

Shells;  Use  of  oyster,  clam  and  other  shells;  Cause  of  the  crackling  noise 
of  shells  when  the  heat  first  strikes  them;  Marble  spalls  .  .  .  142 

Experiments  with  mineral  and  chemical  materials  with  the  view  of 
making  a  cheap  malleable  iron;  Reasons  why  iron  is  often  ruined  as 
a  foundry  iron  by  improper  melting  and  fluxing;  Increase  in  the  per 
cent,  of  iron  lost  in  melting  by  improper  melting  and  fluxing  .  .  143 

Effect  of  silicon  on  iron;  Per  cent,  of  silicon  an  iron  may  contain;  Use 
at  the  present  time  of  high  silicon  cheap  southern  iron  .  .  .144 

Heavy  breakage  due  to  the  use  of  high  silicon  irons;  Effect  of  carbon 
upon  cast  iron;  Removal  of  free  carbon  from  iron  ....  145 

Fluor  spar,  and  its  use  as  a  flux 146 

Cleaning  iron  by  boiling;  Poling  molten  iron   ......  147 

CHAPTER  VII. 
DIFFERENT  STYLES  OF  CUPOLAS. 

Old  Style  Cupolas. 

Old  style  cupola  in  general  use  throughout  this  country  many  years  ago, 
described  and  illustrated  .         .........  149 

Practice  of  casting  with  the  use  of  the  old-style  cupola    .         .         .         .151 

The  reservoir  cupola,  described  and  illustrated 152 

Stationary  bottom  cupola;  Old  style  English  cupola,  described  and  illus- 
trated   154 

Expanding  cupola,  described  and  illustrated     .         .        .        .         .         .  155 


Xii  CONTElSfTS. 

PAGE 

Ireland's  cupola,  described  and  illustrated        .         .         ...         .  157 

Ireland's  center  blast  cupola,  described  and  illustrated     .         .         .         .159 

Voisin's  cupola,  described,  and  illustrated  .......  161 

Woodward's  steam-jet  cupola,  described  and  illustrated  ....  163 

Objection  to  this  style  of  cupola;  Tank  or  reservoir  cupola,  described 

and  illustrated 167 

Production  of  soft  iron  by  putting  a  quantity  of  charcoal  on  the  sand 

bottom;  Use  of  tanks  in  England        ........  169 

Mackenzie  cupola,  described  and  illustrated      .         .         .         .         .         .170 

Management  of  the  Mackenzie  cupola       .......  172 

The  Herbertz  cupola,  described  and  illustrated;  Movable  hearth  of  this 

cupola 173 

Advantages  of  the  application  of  a  steam  jet  to  create  draft  in   the 

cupola 175 

Test  heats  with  the  Herbertz  cupola »  176 

Composition  of  the  escaping  gases  from  the  Herbertz  cupola  .         .         .  177 
Explanation  why  less  carbon  and  silica  are  eliminated  from  the  iron  in 

the  Herbertz  cupola  than  in  the  ordinary  blown  cupola        .         .         .  178 
Working  of  the  Herbertz  cupola  at  Elizabethport,  N.  J    .         .         .         .179 

The  hearth  in  the  cupola  used  at  Elizabethport 180 

Process  of  melting;  Results  of  test -heats  at  Elizabethport        .         .         .  181 
Herbertz's  cupola   used  for  melting  steel,  described   and  illustrated; 

Melting  bronze.         ...........  182 

Pevie  cupola,  described  and  illustrated      .......  184 

Object  of  Mr.  Pevie  in  constructing  a  cupola;  Stewart's  cupola,  described 

and  illustrated 186 

Rapid  melting  of  this  cupola;  The  Greiner  patent  economical  cupola, 

described  and  illustrated .188 

What  the  novelty  of  this  invention  consists  of .         .         .         .  .189 

Principle  of  the  workings  of  the  Greiner  cupola  illustrated     .         .         .  190 

Mr.  Greiner' s  conclusions. 191 

Points  in  favor  of  the  Greiner  cupola;  Colliau  patent  hot-blast  cupola, 

described  and  illustrated 192 

History  and  description  of  the  cupola  and  results  obtained  in  melting    .  193 

Claims  made  for  the  Colliau  furnace 194 

The  Whiting  cupola,  described  and  illustrated 196 

Jumbo  cupola,  described  and  illustrated    .......  198 

Charge  table  for  the  Jumbo  cupola    ........  200 

The  Crandall  improved  cupola  with  Johnson  patent  center  blast  tuyere, 

described  and  illustrated 202 

Mode  of  applying  the  air  to  this  cupola    .......  203 

Claims  made  for  the  Crandall  cupola;  Blakeney  cupola,  described  and 

illustrated 204 

Advantages  of  this  cupola  ..........  205 


CONTENTS.  Xiii 

CHAPTER  VIII. 
ART  IN  MEETING. 

PAGE 

The  art  of  melting  iron  in  a  cupola  but  little  understood  by  many 
foundrymen  and  foundry  foremen;  Troubles  experienced  in  melting.  206 

No  chance  work  in  nature  or  in  art;  Necessity  of  understading  the  con- 
struction and  mode  of  operation  of  a  cupola  to  do  good  melting  .  .  207 

Location  and  arrangement  of  the  tuyeres;  Preparation  of  the  cupola  for 
a  heat;  Lighting  up  ..........  208 

Melting  iron  in  a  cupola  a  simple  process;  Things  to  be  learned  and 
practiced;  Necessity  of  a  close  study  of  all  the  materials  used  in  melt- 
ing .  . 209 

What  should  be  the  aim  of  every  moulder;  Advisability  of  the  foreman 
of  a  foundry  being  the  melter;  Duties  of  the  melter  .  .  .  .210 


CHAPTER  IX. 

SCALES  AND  THEIR  USE. 

Necessity  of  an  accurate  scale  upon  the  scaffold;  Size  of  scale  required; 
What  the  melting  of  iron  in  a  cupola,  when  reduced  to  an  art,  consists 
in 211 

Division  of  the  fuel  and  iron  into  charges;  The  theory  of  melting  not 
understood  by  many  foundrymen;  Incorrect  methods  of  calculating 
the  charges  of  iron  and  fuel  .........  212 

Use  of  old,  worn-out  scales  condemned     .......  213 

CHAPTER  X. 
THE  CUPOLA  ACCOUNTS. 

Value  of  cupola  records;  Manner  of  keeping  the  accounts       .         .         .  214 

Cupola  report  of  Abeudroth  Bros.,  Port  Chester,  N.Y 215 

Cupola  report  of  Byram  &  Co.,  Iron  Works,  Detroit,  Mich.     .        .         .216 
Daily  report  of  Foundry  Department,  Lebanon  Stove  Works  .         .         .  217 

Melting  sheet  of  Syracuse  Stove  Works 218 

Report  of  castings  in  Shop      .....         ...  219 

Cupola  slate  for  charging  and  cupola  report 220 

Blanks  for  reports  and  records  and  mode  of  making  them  out;  Report 
on  a  slate;  Correctness  essential  to  the  value  of  a  cupola  account  .  221 

CHAPTER  XI. 

PIG  MOULD  FOR  OVER  IRON. 
Saving  in  iron  and  labor  by  the  use  of  cast  iron  pig  moulds  for  collecting 


over  iron 


222 


XIV  CONTENTS. 

CHAPTER  XII. 
WHAT  A  CUPOLA  WILL  MELT. 

PACK 

Chief  use  of  the  cupola  furnace;  Employment  of  the  cupola  furnace  for 
other  purposes  than  melting  iron 223 

Quantity  of  iron  that  can  be  melted  in  a  cupola;  Number  of  hours  a 
cupola  may  be  run;  Size  and  weight  of  a  piece  of  cast-iron  that  can  be 
melted  in  a  cupola;  Charging  large  pieces  of  iron  at  the  foundry  of 
Pratt  &  Whitney  Co.,  Hartford,  Conn.;  Melting  of  cannon  and  other 
heavy  government  scrap  at  the  L/obdell  Car  Wheel  Co.,  Wilmington, 
Del 224 

CHAPTER  XIII. 

MELTING  TIN  PLATE  SCRAP  IN  A  CUPOLA. 

Various  ways  of  preparing  the  scrap  for  charging;  Attempts  to  recover 
the  tin  deposited  upon  the  iron;  Quality  of  the  molten  metal  from  the 
scrap 225 

Susceptibility  of  the  molten  metal  to  the  effect  of  moisture;  Uses  of  the 
metal;  Production  of  a  gray  metal  from  the  scrap;  Tests  to  learn  the 
amount  of  metal  lost  in  melting  the  scrap  .  .....  226 

Action  of  tin  as  a  flux  when  melted  with  iron;  Unsuitability  of  galvan- 
ized sheet-iron  scrap  for  melting  in  a  cupola;  Doctoring  the  metal 
from  tin-plate-scrap;  Process  of  melting  tin-plate-scrap  .  .  .  227 

Fluxing  tin-plate-scrap;  Construction  of  a  cupola  expressly  for  melting 
tin-plate-scrap  ... .  228 

Cost  of  melting  tin-plate-scrap  and  profit  in  the  business.         .         .         .  229 

CHAPTER  XIV. 

COST  OF  MELTING. 

Unreliability  of  melting  accounts  as  generally  kept;  Objection  to  measur- 
ing fuel  in  baskets 230 

Results  of  an  accurate  account  of  the  melting  in  a  foundry  in  New  Jer- 
sey; Cupola  book;  Proper  method  of  figuring  the  cost  of  melting  per 
ton 231 

CHAPTER  XV. 

EXAMPLES  OF  BAD  MELTING. 
Necessity  of  giving  causes  of  poor  melting;  Trouble  with  the  cupolas  at 

the  stove  foundry  of  Perry  &  Co.,  Sing  Sing,  N.  Y 233 

Cause  of  the  trouble;  Sectional  views  of  lining  out  of  shape     .         .         .  236 

Remedy  of  the  troubles 240 

Bad  melting  at  a  West  Troy  Stove  Works;  Visit  at  the  foundry  of  Daniel 
E.  Paris  &  Co.,  West  Troy,  N.  Y.;  Inspection  of  the  foundry  with  a 
view  of  locating  the  trouble .  .  .  242 


CONTENTS.  XV 

PAGE 

Trouble  due  to  the  use  of  too  much  fuel 243 

Experiment  of  running  the  cupola  with  less  fuel ;  Objection  of  the 

melter  to  the  experiment        .........  244 

Result  of  the  experiment;  Heats  with  a  still  further  reduction  of  fuel     .  246 
Cause  of  bad  melting  in  this  foundry         .......  247 

Warming  up  a  cupola;  Visit  to  the  plant  of  the  Providence  Locomotive 

Works;  Trouble  with  the  cupola 248 

Cause  of  the  poor  melting  due  to  the  bed  being  burned  too  much  .  .  249 
Remedy  of  the  trouble;  Bad  melting,  caused  by  wood  and  coal;  Cause 

of  poor  melting  in  one  of  the  leading  novelty  foundries  in  Philadelphia  250 
Poor  melting  in  a  Cincinnati  cupola;  Sectional  elevation  showing  the 

condition  of  the  cupola    ..........  251 

Uneven  burning  of  the  bed ;  Reason  for  the  necessity  of  dumping  a 

cupola  at  the  foundry  of  Perry  &  Co.     .......  253 


CHAPTER  XVI. 

MEI/TERS. 

Respect  due  to  the  practical  and  scientific  melter;  Unfortunate  position 
of  a  poor  melter;  Interference  with  a  good  melter  frequently  the  cause 
of  poor  melting 254 

Necessity  of  furnishing  proper  tools  for  chipping  out,  and  making  up 
the  cupola;  What  should  be  the  aim  of  every  melter  ....  255 

Interest  of  every  foundryman  to  keep  his  melter  posted  ....  256 


CHAPTER  XVII. 

EXPLOSION  OF  MOI/TEN  IRON. 

Conditions  under  which  molten  iron  is  explosive;  Explosions  caused  by 
a  wet  spout  or  a  wet  bod 257 

Cause  of  sparks;  Various  causes  of  the  explosion  of  molten  iron;  Explo- 
sion due  to  thrusting  a  piece  of  cold,  wet  or  rusted  iron  into  molten 
iron 258 

Explosion  of  molten  iron  when  poured  into  a  damp  or  rusted  chill- 
mould  or  a  wet  sand-mould;  Accident  in  the  foundry  of  Wm.  McGil- 
very  &  Co.,  Sharon,  Pa 259 

Explosion  of  molten  iron  when  poured  into  mud  or  brought  into  contact 
with  wet  rusted  scrap;  Accident  in  the  foundry  of  James  Marsh,  Lewis- 
burg,  Pa.;  Accident  at  the  foundry  of  North  Bros.,  Philadelphia,  Pa.  260 

Explosion  at  the  foundry  of  the  Skinner  Engine  Co.,  Erie,  Pa.,  and  at 
the  foundry  of  the  Buffalo  School  Furniture  Co.,  Buffalo,  N.  Y.  .  .261 

Prevention  of  explosions     ..........  262 


xvi  CONTENTS. 

CHAPTER  XVIII. 
SPARK-CATCHING  DEVICES  FOR  CUPOLAS. 

PAGE 

Spark-catcher  in  old-style  cupolas 263 

Spark-catching  device  for  modern  cupolas .  264 

Return  flue  cupola  spark-catcher,  designed  by  John  O.  Keefe.         .        .  266 
Other  spark-catching  devices      .........  268 

The  best  spark- catching  device;  Cause  of  sparks  being  thrown  from  a 
cupola;  Prevention  of  sparks  being  carried  out  of  the  stack;  Enlarged 
stack 269 

CHAPTER  XIX. 

HOT  BLAST  CUPOLAS. 

Hot  blast  cupolas  constructed  by  Jagger,  Treadwell  &  Perry  .         .         .  271 
Cupola  at  the  foundry  of  Ransom  &  Co.,  Albany,  N.  Y.;  Arrangement 

with  exhaust  pipes  ...........  273 

Heating  the  blast  for  a  cupola;  Waste  heat  from  a  cupola;  Plans  for 

utilizing  the  heat  escaping  from  a  cupola       ......  274 

Cupolas  at  the  Carnegie  Steel  Works,  Homestead,  Pa.;  Prevention  of 

the  escape  of  heat  in  low  cupolas 275 

CHAPTER  XX. 

TAKING  OFF  THE  BLAST  DURING  A  HEAT — BANKING  A  CUPOLA — BLAST 
PIPES,  BLAST  GATES. 

Explosions  in  blast  pipes,  blast  gauges,  blast  in  melting;  Length  of  time 
the  blast  can  be  taken  off  a  cupola;  Management  of  a  cupola  from 
which  the  blast  is  taken  off 276 

Banking  a  cupola;  Communication  from  Mr.  Knoeppel,  Foundry  Super- 
intendent, Buffalo  Forge  Co.,  Buffalo,  N.  Y.,  on  banking  a  cupola  .  277 

Blast  pipes;  Importance  of  the  construction  and  arrangement  of  blast 
pipes;  Underground  blast  pipes 279 . 

Objection  to  underground  blast-pipes;  Materials  used  in  the  construction 
of  blast-pipes;  Galvanized  iron  pipes  .......  280 

Table  prepared  by  the  Buffalo  Forge  Co  ,  Buffalo,  N.  Y.,  as  a  guide  for 
increasing  the  diameter  of  pipes  iu  proportion  to  the  length;  Diameter 
of  blast-pipes;  Friction  in  pipes 281 

Frequent  cause  of  a  blower  being  condemned  as  being  insufficient.         .  282 

Table  showing  the  necessary  increase  in  diameter  for  the  different 
lengths 283 

Connection  of  blast  pipes  with  cupola  ;  Combined  area  of  the  branch 
pipes 284 

Table  of  diameter  and  area  of  pipes 285 

Connecting  blast  pipes  direct  with  tuyeres ;  Perfect  connection  of  air 
chambers;  Poor  arrangement  of  pipes  in  a  "perfect  cupola"  .  .  286- 


CONTENTS.  xvii 


Mode  of  connecting  a  belt-air  chamber  with  the  tuyeres;  Best  way  of 
connecting  blast  pipes  with  cupola  tuyeres  ......  288 

Blower  placed  near  cupola 289 

Poor  melting  often  caused  by  long  blast  pipes;  Perfect  manner  of  con- 
necting the  main  pipe  with  an  air  chamber;  Blast  gates;  Advantage  of 
the  employment  of  the  blast  gate 290 

Explosions  in  blast  pipes;  Prevention  of  such  explosions;  Blast  gauges; 
Variety  of  gauges  ...........  292 

What  an  air-gauge  to  be  of  any  value  in  melting  must  indicate       .         .  293 

Blast  in  melting;  Means  for  supplying  the  required  amount  of  air  to  the 
cupola;  Machines  for  supplying  the  blast;  Relative  merits  of  a  posi- 
tive and  non-positive  blast  .......  .  294 

Amount  of  air  required  for  combustion  of  the  fuel  in  melting  a  ton  of 
iron 295 

Theory  of  melting  in  the  old  cupolas  with  small  tuyeres;  Necessity  of 
discarding  the  small  tuyeres  .........  296 

Points  to  be  remembered  in  placing  tuyeres  in  a  cupola;  Best  tuyere  for 
large  cupolas;  Size  of  the  largest  cupolas  in  which  air  can  be  forced  to 
the  center  from  side  tuyeres  .  ........  297 

Cupolas  of  the  Carnegie  Steel  Works,  Homestead,  Pa. ;  Experiments 
with  a  center  blast  tuyere 298 

Claims  for  the  center  blast 299 

CHAPTER  XXI. 

BLOWERS. 

Placing  a  blower;  Convenient  way  of  placing  a  blower  near  a  cupola  .  30(J 
Fan  blowers;  Buffalo  steel  pressure  blower;  Claims  for  this  blower  .  301 
Blower  on  adjustable  bed,  and  on  bed  combined  with  countershaft  .  303 
Blower  on  adjustable  bed,  combined  with  double  upright  engine  .  .  305 
Buffalo  electric  blower  built  in  "  B  "  and  steel  pressure  types  .  .  .  306 
Buffalo  blower  for  cupola  furnaces  in  iron  foundries  ....  308 
Table  of  speeds  and  capacities  as  applied  to  cupolas;  Smith's  Dixie  fan 

blower 309 

Forced  blast  pressure  blowers;  The  Mackenzie  blower    .         .        .         .311 

Description  of  and  claim  for  this  blower 312 

Sizes  of  the  Mackenzie  blower;  Construction  and  operation  of  the  ma- 
chine   313 

Directions  for  setting  up  blower;  The  Green  patented  positive  pressure 
blower;  Claims  for  this  blower        .         .  .....  314 

Complete  impeller,  Illustrated  and  described;  Directions  for  setting  up 

blower 316 

Efficiency  of  blower    .         .         .         .         .         .         .         <         .         .        .317 

Power;  Rule  for  estimating  the  approximate  amount  of  power  required 
to  displace  a  given  amount  of  air  at  a  given  pressure  .  .  .  .318 


xviii  CONTENTS. 


Standard  foundry  blowers  driven  by  steam,  dimensions  in  inches  .         .  319 

Speed  of  foundry  blowers 320 

Connersville  cycloidal  blower 321 

Special  value  of  combining  the  epi-  and  hypo-cycloids  to  form  the  con- 
tact surfaces  of  impellers.         .         .         .         .         .         .        .         .  322 

Advantages  claimed  for  the  Connersville  cycloidal  blower       .         .         .  323 
Table  of  numbers,  capacities,  etc.,  of  the  cycloidal  blowers;  What  is 
meant  by  ordinary  speed;  Vertical  blower  and  engine  on  same  bed 

plate 326 

Blower  and  electric  motor 327 

Garden  City  positive  blast  blowers 328 

Root's  rotary  positive  pressure  blower      .......  329 

Claims  for  this  blower 330 

CHAPTER  XXII. 

CUPOLAS  AND  CUPOLA  PRACTICE  UP  TO  DATE. 

Kinds  of  furnaces  employed  in  the  melting  of  iron  for  foundry  work; 
Coke  the  almost  universal  fuel  for  foundry  work;  Quantity  of  fuel 
required  in  the  different  kinds  of  furnaces 332 

Rule  for  charging  a  cupola;  Height  or  distance  the  tuyeres  should  be 
placed  above  the  sand  bottom.  ........  333 

Function  of  the  fuel  placed  below  the  tuyeres;  Fallacy  of  the  claim  that 
it  is  necessary  to  have  tuyeres  placed  high  to  collect  and  keep  iron 
hot  for  a  large  casting;  Objection  to  low  charging  doors  .  .  .  334 

Highest  cupolas  in  use  in  this  country;  What  is  required  for  a  cupola  to 
do  economical  melting;  Determination  of  the  top  of  the  melting  zone.  335 

Tests  to  ascertain  the  amount  of  fuel  required  in  the  charges  and  the 
amount  of  iron  that  can  be  melted  upon  each  charge;  General  con- 
sumption of  too  great  an  amount  of  fuel  ......  336 

On  what  the  per  cent,  of  fuel  required  in  melting  depends;  Necessity  of 
reducing  the  melting  to  a  system;  Advisability  of  keeping  an  accurate 
cupola  record 337 

CHAPTER  XXIII. 

CUPOLA  SCRAPS. 

Brief  paragraphs  illustrating  important  principles;  Terms  used  in  differ- 
ent sections  of  the  country  to  indicate  the  melting  of  iron  in  a  cupola.  339 
Best  practical  results  for  melting  for  general  foundry  work     .         .         .  343 
Remarks  by  Mr.  C.  A.  Treat;  Difficulty  experienced  by  a  foundryman 
in  obtaining  reliable  cupola  reports  for  publication        ....  344 

NOTE. 
Paxson-Colliau  Cupola 345 

Index  .  .  347 


CHAPTER  I. 

THE   CUPOLA   FURNACE. 

THE  cupola  furnace  has  many  advantages  over  any  other 
kind  of  furnace  for  foundry  work. 

It  melts  iron  with  less  fuel  and  more  cheaply  than  any  other 
furnace,  can  be  run  intermittently  without  any  great  damage 
from  expansion  and  contraction  in  heating  and  cooling.  Large 
or  small  quantities  of  iron  may  be  melted  in  the  same  furnace 
with  very  little  difference  in  the  per  cent,  of  fuel  consumed,  and 
the  furnace  can  readily  be  put  in  and  out  of  blast.  Conse- 
quently in  all  cases  where  the  strength  of  the  metal  is  not  of 
primary  importance,  the  cupola  is  to  be  preferred  for  foundry 
work. 

In  the  reverberatory  furnace  from  ten  to  twenty  cwt.  of  fuel 
is  required  to  melt  one  ton  of  iron. 

In  the  pot  furnace  one  ton  of  coke  is  consumed  in  melting  a 
ton  of  cast  iron,  and  two  and  a  half  tons  in  melting  a  ton  of 
steel. 

In  the  blast  furnace  twenty  to  twenty-five  cwt.  of  coke  is  con- 
sumed in  the  production  of  a  ton  of  pig  iron. 

In  the  cupola  furnace  a  ton  of  iron  is  melted  with  from  172 
to  224  Ibs.  of  coke. 

It  will  thus  be  seen  that  in  the  cupola  furnace  we  have  the 
minimum  consumption  of  fuel  in  melting  a  ton  of  iron,  although 
the  amount  consumed  is  still  three  or  four  times  that  theoret- 
ically required  to  do  the  work. 

Many  attempts  have  been  made  to  decrease  even  this  small 
amount  of  fuel  consumed  in  the  cupola,  by  utilizing  the 
waste  heat  passing  off  from  the  top  for  heating  the  blast.  But 


2  THE   CUPOLA   FURNACE. 

the  cupola  being  only  intermittently  at  work  has  rendered  all 
such  attempts  futile. 

The  cupola  furnace  is  a  vertical  furnace  consisting  of  a  hollow 
casing  or  shell,  lined  with  fire-brick  or  other  refractory  material, 
resting  vertically  upon  a  cast  iron  bottom  plate,  having  an 
opening  in  the  centre  equal  to  the  inside  diameter  of  the  lining 
and  corresponding  in  shape  to  the  shape  of  the  furnace.  This 
opening  is  closed  with  iron  doors  covered  with  sand  when  the 
furnace  is  in  blast.  Two  or  more  openings  are  provided  near 
the  bottom  of  the  furnace  for  the  admission  of  air  by  draught 
or  forced  blast.  A  small  opening,  on  a  level  with  the  bottom 
plate,  is  arranged  for  drawing  off  the  molten  metal  from  the 
furnace.  An  opening,  known  as  the  charging  door,  is  made  in 
the  side  of  the  casing  at  the  top  of  the  furnace  for  feeding  it 
with  fuel  and  iron,  and  a  stack  or  chimney  is  constructed 
above  the  charging  door  for  carrying  off  the  escaping  smoke, 
heat  and  gases. 

Cupolas  have  been  constructed  cylindrical,  elliptical,  square 
and  oblong  in  shape,  and  they  have  been  encased  in  stone, 
brick,  cast  iron  and  wrought  iron  casings.  From  one  to  a 
hundred  or  more  tuyeres  have  been  placed  in  a  cupola,  and  the 
stationary  and  drop  bottoms  have  been  used.  At  the  present 
time  cupolas  are  constructed  almost  entirely  in  a  cylindrical  or 
elliptical  form,  and  the  casing  is  made  of  wrought  iron  or  steel 
boiler  plate.  The  stack  casing  is  made  of  the  same  material 
and  is  extended  up  to  a  sufficient  height  to  give  draught  for 
lighting  up,  and  to  carry  off  the  escaping  heat  and  gases.  The 
drop  bottom  has  been  almost  universally  adopted,  at  least  in 
this  country. 

Cupolas  are  constructed  of  various  sizes,  to  suit  the  require- 
ments of  the  foundry  they  are  to  supply  with  molten  metal. 
Those  of  large  size  are,  when  charged  with  iron  and  fuel,  of 
immense  weight,  and  require  a  very  solid  foundation  to  support 
them.  The  foundation  is  generally  made  of  solid  stone  work 
up  to  the  level  of  the  foundry  floor ;  upon  this  is  placed  brick 
work  laid  in  cement,  or  cast  iron  columns  or  posts,  for  the  sup- 


THE   CUPOLA   FURNACE.  3 

port  of  the  iron  bottom  and  cupola.  In  all  cases  where  the 
cupola  is  set  at  sufficient  height  from  the  floor  to  admit  of  the 
use  of  the  iron  supports  they  are  to  be  preferred  to  brick-work, 
as  they  admit  of  more  freedom  in  removing  the  dump  and  re- 
pairing the  lining.  The  columns  or  posts  are  placed  at  a  suffi- 
cient distance  apart  to  permit  the  drop  doors  to  swing  free 
between  them.  This  arrangement  removes  the  liability  to 
breaking  the  doors  by  striking  the  cupola  supports  in  falling, 
and  admits  of  their  being  put  back  out  of  the  way  when  remov- 
ing the  dump. 

The  height  the  bottom  of  the  cupola  is  placed  above  the 
moulding  floor  depends  upon  the  size  of  the  ladles  to  be  filled, 
and  varies  from  fourteen  inches  to  five  feet.  If  placed  too  high 
for  the  sized  ladle  used,  considerable  iron  is  lost  by  sparks  and 
drops  separating  from  the  stream  in  falling  a  long  distance,  and 
the  stream  is  more  difficult  to  catch  in  the  ladles.  For  hand 
ladle  work  it  is  better  to  place  the  cupola  a  little  higher  than  four- 
teen inches,  and  rest  the  ladle  upon  a  hollow  oblong  pedestal 
eight  or  ten  inches  high,  and  open  at  both  ends,  than  to  set  it 
upon  the  floor.  The  ladle  can  then  be  moved  back  or  forward 
to  catch  the  stream,  and  iron  spilled  in  changing  ladles  falls 
inside  the  pedestal,  and  is  prevented  from  flying  when  it  strikes 
the  hard  floor,  and  is  collected  in  one  mass  inside  the  pedestal. 
This  arrangement  reduces  the  liability  of  burning  the  men 
about  the  feet  and  renders  it  easier  to  lift  the  full  ladle. 

If  a  cupola  is  set  very  low,  it  is  then  necessary  to  make  an 
excavation  or  pit  beneath  it  to  permit  of  the  removal  of  the 
dump,  and  repairing  of  the  lining.  This  pit  is  made  as  wide  as 
it  conveniently  can  be,  and  of  a  length  equal  to  two  or  three 
times  the  diameter  of  the  cupola.  The  distance  from  the 
bottom  plate  to  the  bottom  of  the  pit  should  not  be  less  than 
three  feet.  The  bottom  of  the  pit  is  lined  with  a  hard  quality 
of  fire-brick  set  on  edge,  and  the  floor  sloped  from  the  edges  to 
the  centre,  and  from  the  end  under  the  cupola  outward,  so  that 
any  molten  iron  falling  writhin  the  dump  will  flow  from  under 
the  cupola,  and  thus  facilitate  its  removal.  In  the  centre  of  the 


4  THE   CUPOLA   FURNACE. 

pit  under  the  cupola  a  block  of  stone  or  a  heavy  block  of  iron 
is  securely  placed,  upon  which  to  rest  the  prop  for  the  support 
of  the  iron  bottom  doors. 

The  bottom  plate  is  made  of  cast  iron,  and  must  be  of 
sufficient  thickness  and  properly  flanged  or  ribbed  to  prevent 
breaking.  If  broken  when  in  place,  it  can  not  be  removed,  and 
it  is  then  almost  impossible  to  securely  bolt  it  so  as  to  hold 
it  in  place.  The  plate  must  be  firmly  placed  upon  the  iron  sup- 
ports or  brick  work,  so  that  no  uneven  strain  will  be  put  upon 
it  by  the  weight  of  the  cupola  and  stack. 

The  bottom  doors  are  made  in  one  piece  or  in  two  or  more 
sections.  For  large  cupolas  they  are  generally  made  in  two  or 
four  sections  to  facilitate  raising  them  into  place.  Bottom 
doors  are  made  of  cast  or  wrought  iron.  Those  made  of  cast 
iron  are,  when  in  place,  the  stiffest  and  firmest.  Those  made 
of  wrought  iron  are  the  lightest  and  easiest  to  handle,  but  are 
also  more  liable  to  be  warped  by  heat  in  the  dump,  and  to 
spring  when  in  place.  The  door,  or  doors,  whether  made  of 
cast  or  wrought  iron,  have  wide  flanges  to  overlap  the  bottom 
plate  and  each  other  when  in  place,  to  prevent  the  sand,  when 
dry,  running  out  through  cracks  and  making  holes  in  the  sand 
bottom.  The  doors  are  supported  in  place  by  a  stout  iron  or 
wooden  prop ;  and  when  the  doors  are  light,  or  sprung,  one  or 
more  additional  props  are  put  in  for  safety.  Numerous  bolts 
and  latches  have  been  devised  for  holding  the  doors  in  place, 
but  they  have  all  been  abandoned  in  favor  of  the  prop,  which 
is  the  safest.  Sliding  doors,  or  plates,  have  been  arranged 
upon  rollers  to  slide  into  place  under  the  cupola  from  the  sides, 
and  be  withdrawn  by  a  ratchet  or  windlass  to  dump  the  cupola. 
They  admit  of  easy  manipulation ;  but  in  case  of  leakage  of 
molten  iron  through  the  sand  bottom,  they  are  sometimes  burnt 
fast  to  the  bottom  plate  and  cannot  be  withdrawn,  and  for  this 
reason  the  sliding  door  is  seldom  used. 

The  casings  are  made  of  cast  or  wrought  iron  plate.  When 
made  of  cast  iron  they  are  cast  in  staves,  which  are  put  in  place 
on  the  iron  bottom  and  bound  together  by  wrought  iron  bands  ; 


THE    CUPOLA   FURNACE.  5 

these  bands  being  shrunk  on.  Or  they  are  cast  in  cylindrical 
sections,  which  are  placed  one  on  top  of  another,  and  bolted 
together  by  the  flanges.  This  kind  of  casing  generally  cracks 
from  expansion  and  shrinkage  in  a  short  time,  and  is  the  poor- 
est kind  of  casing.  With  the  cast  iron  casing  a  brick  stack, 
constructed  upon  a  cast  iron  plate  supported  by  four  iron  col- 
umns, is  generally  used.  The  wrought  iron  casing  is  more 
generally  employed  at  the  present  time  than  that  of  cast  iron. 
It  is  made  of  boiler  plate,  securely  riveted  together  with  one 
or  two  rows  of  rivets ;  but  one  row  of  rivets,  and  those  three 
inches  apart,  is  generally  found  to  be  sufficient,  as  the  strain 
upon  the  casing,  when  properly  lined,  is  not  very  great. 

The  stack  casing  is  generally  made  of  the  same  material  as 
that  of  the  cupola,  and  is  a  continuation  of  the  cupola  casing; 
the  two  generally  being  made  in  one  piece. 

The  stack  is  made  the  same  size  as  the  cupola,  or  is  con- 
tracted or  enlarged  according  to  the  requirements  or  fancy  of 
the  foundryman.  A  contracted  stack  gives  a  good  draught, 
but  throws  out  a  great  many  sparks  at  the  top.  An  enlarged 
stack  gives  a  poor  draught,  unless  it  is  very  high,  but  throws 
out  very  few  sparks  at  the  top.  As  sparks  are  very  objection- 
able in  some  localities,  and  not  in  others,  different  sized  stacks 
are  used.  When  surrounded  by  high  buildings  or  hills,  the 
stack  must  be  made  of  sufficient  height  to  give  the  necessary 
draught  for  lighting  up  in  all  kinds  of  weather,  and  they  vary 
in  height  from  a  few  feet  above  the  foundry  roof  to  twenty  or 
thirty  feet.  Bands  of  angle  iron  are  sometimes  riveted  to  the 
inside  of  the  cupola  and  stack  casing  to  support  the  lining,  and 
admit  of  sections  being  taken  out  and  replaced  without  remov- 
ing the  entire  lining. 

The  casing  and  lining  are  perforated  with  two  or  more  tuyere 
holes  near  the  bottom,  for  the  admission  of  air  by  draught  or 
forced  blast.  These  tuyeres,  when  supplied  with  a  forced 
blast,  are  connected  with  the  blower  by  branch  pipes  to  each 
tuyere,  or  are  supplied  from  an  air  chamber  riveted  to  the 
cupola  casing  either  on  the  outside  or  inside.  The  air  chamber 


6  THE   CUPOLA    FURNACE. 

is  made  three  or  four  times  the  area  of  the  blast  pipe,  and  is  sup- 
plied from  the  blast  pipe  connecting  it  with  the  blower.  An 
opening  is  made  through  the  casing  and  lining,  just  above  the 
bottom  plate,  for  drawing  the  molten  iron  from  the  cupola,  and 
a  short  spout  is  provided  for  running  it  into  the  ladles.  An- 
other small  opening  is  sometimes  made,  just  under  the  lower 
level  of  the  tuyeres,  for  tapping  or  drawing  off  the  slag  from 
the  cupola.  This  opening  is  never  used  except  when  a  large 
amount  of  iron  is  melted,  and  the  cupola  is  kept  in  blast  for  a 
number  of  hours. 

An  opening  for  feeding  the  furnace,  known  as  the  charging 
door,  is  placed  in  the  cupola  at  a  height  varying  from  six  to 
twenty  feet  above  the  bottom  plate,  according  to  the  diameter 
of  the  cupola.  This  opening  is  sometimes  provided  with  a 
cast  iron  frame  or  casing  on  the  inside  to  protect  the  lining 
around  the  door  when  putting  in  the  fuel  and  iron.  A  door 
frame  is  placed  upon  the  outside,  upon  which  are  cast  lugs-  for  a 
swinging  door,  or  grooves  for  a  sliding  door.  The  door  for 
closing  the  charging  aperture  may  consist  of  a  cast  or  wrought 
iron  frame  filled  with  fire-brick,  or  be  made  of  boiler  plate  with 
a  deep  flange  all  around  for  holding  fire-brick  or  other  refrac- 
tory material.  The  sliding  door  consists  of  an  iron  frame 
filled  in  with  fire-brick,  and  is  hung  by  the  top,  and  moved  up 
and  down  with  a  lever  or  balance  weights.  This  door  is  moved 
up  and  down  in  grooves  cast  upon  the  door  frames,  which 
grooves  frequently  get  warped  by  the  heat,  and  hold  the  door 
fast.  The  hinge  or  swing  door,  with  plenty  of  room  for  expan- 
sion and  shrinkage,  is  the  door  generally  used. 

The  casing  is  lined  from  the  bottom  plate  to  the  top  of  the 
stack  with  a  refractory  material.  A  soft'  refractory  fire-brick, 
laid  up  with  a  grout  composed  of  fire-clay  and  sand,  is  used  for 
lining  in  localities  where  such  material  can  be  obtained.  In 
localities  where  fire-brick  can  not  be  procured,  soapstone  from 
quarries  or  the  bottoms  of  small  creeks,  is  laid  up  with  a  re- 
fractory clay.  Some  grades  of  sandstone  or  other  refractory 
substances  are  also  employed  for  lining.  Native  refractory 


THE   CUPOLA   FURNACE.  7 

materials  are  seldom  homogeneous,  and  those  which  have  been 
.ground  and  moulded,  or  pressed  into  blocks,  make  the  best  lin- 
ings. The  thickness  of  the  lining  varies  in  large  and  small 
cupolas.  Those  in  the  large  cupolas  are  from  six  to  nine 
inches,  and  in  small  cupolas  from  four  to  six  inches. 

The  cupola  charging  aperture  is  placed  at  too  great  a  height 
from  the  floor  to  admit  of  the  cupola  being  charged  or  loaded 
rom  the  floor,  and  a  scaffold  or  platform  is  erected  from  which 
to  charge  it.  The  scaffold  is  generally  placed  in  the  rear  of  the 
cupola,  so  as  to  be  out  of  the  way  when  removing  the  molten 
iron  in  crane  ladles.  But  for  hand  ladle  work  it  is  placed  at 
any  point  most  convenient  for  getting  up  the  stock,  and  the 
charging  aperture  placed  in  the  cupola  at  any  point  most  con- 
venient for  charging.  For  very  large  cupolas  the  scaffold  is 
frequently  constructed  to  extend  all  around  the  cupola,  and  a 
charging  aperture  is  placed  in  the  cupola  on  each  side,  so  that 
it  may  be  more  rapidly  charged.  The  scaffold  is  constructed 
of  wood  or  iron  frame  work,  or  is  supported  by  a  brick  wall. 
The  floor  is  placed  level  with  the  bottom  of  the  charging 
aperture,  or  is  placed  from  one  to  two  feet  below  it.  The  scaf- 
fold should  be  made  large  enough  to  place  a  weighing  scale 
in  front  of  the  charging  door,  to  hold  iron  and  fuel  for  several 
heats,  and  have  plenty  of  room  for  handling  the  stock  when 
stocking  the  scaffold  and  charging  the  cupola.  Nine-tenths  of 
the  scaffolds  are  too  small  for  the  work  to  be  done  on  them, 
and  the  cupola  men  work  to  a  great  disadvantage  when  hand- 
ling the  stock.  Much  of  the  bad  melting  done  in  foundries 
can  be  traced  directly  to  the  lack  of  room  on  the  scaffold  for 
properly  charging  the  cupola. 

Having  thus  given  a  general  outline  description  of  the  cupola 
furnace,  we  shall  in  the  next  chapter  describe  in  detail  where  to 
locate  a  cupola  and  how  to  construct  it. 


CHAPTER  II. 
CONSTRUCTING  A  CUPOLA. 

WHEN  about  to  construct  a  cupola  to  melt  iron  for  foundry 
work,  the  first  thing  to  be  decided  on  is  the  proper  location.  In 
deciding  this  a  number  of  points  are  to  be  taken  into  consider- 
ation, the  two  most  important  of  which  are  the  getting  of  the 
stock  to  the  cupola  and  the  taking  away  of  the  molten  iron.  It 
should  be  borne  in  mind  that  there  is  more  material  to  be 
taken  to  a  cupola  than  is  to  be  taken  away  from  it.  For  this 
reason  the  cupola  should  be  located  as  convenient  to  the  stock 
as  possible.  It  must  also  be  borne  in  mind  that  the  object  in 
constructing  a  cupola  is  to  obtain  fluid  molten  iron  for  the  work 
to  be  cast,  and  if  the  cupola  is  located  at  so  great  a  distance 
from  the  moulding  floors  that  the  molten  metal  loses  its  fluidity 
before  it  can  be  poured  into  the  mould,  the  cupola  fails  in  the 
purpose  for  which  it  was  constructed. 

If  the  work  to  be  cast  is  heavy  and  the  greater  part  of  the 
molten  metal  is  handled  by  traveling  or  swinging  cranes,  the 
small  work  may  be  placed  near  the  cupola  and  the  cupola 
located  at  one  side  or  end  of  the  foundry  near  the  yard.  But 
if  the  work  is  all  light  hand-ladle  or  small  bull-ladle  work,  the 
cupola  should  be  located  near  the  centre  of  the  moulding-room 
so  that  the  molten  iron  may  be  rapidly  conveyed  to  the  moulds 
in  all  parts  of  the  room. 

SCAFFOLD. 

It  is  often  found  difficult,  owing  to  the  shape  of  the  mould- 
ing-room and  location  of  the  yard,  to  place  the  cupola  conven- 
ient for  getting  the  stock  to  it  and  the  molten  iron  away  from 
it.  When  this  is  the  case,  means  must  be  provided  for  getting 

(8) 


CONSTRUCTING  A   CUPOLA.  9 

the  stock  to  the  cupola  and  the  cupola  located  at  a  point  from 
which  the  molten  metal  can  be  rapidly  conveyed  to  the  moulds. 
At  the  present  low  price  of  wrought  iron  and  steel,  a  fire-proof 
cupola  scaffold  can  be  constructed  at  a  very  moderate  cost,  and 
the  difficulty  of  locating  the  cupola  convenient  to  the  yard  may 
be  overcome  by  constructing  a  scaffold  of  a  sufficient  size  to 
take  the  place  of  a  yard  for  iron  and  fuel.  The  scaffold  may 
be  constructed  under  the  foundry  roof  and  made  of  proper 
size  to  hold  one  or  two  cars  of  coal  or  coke,  a  hundred  tons  of 
pig  and  scrap  iron  and  all  the  necessary  material  for  a  cupola. 
The  space  under  the  scaffold  can  be  utilized  as  moulding  floors 
for  light  work  or  for  core  benches,  core  oven,  ladle  oven,  sand- 
bins,  etc.  The  cupola  and  its  supplies  are  then  under  roof,  and 
there  is  no  trouble  from  cupola  men  staying  at  home  in  bad 
weather,  as  is  often  the  case  when  the  cupola  and  stock  are  out 
of  doors. 

When  this  arrangement  is  adopted,  an  endless  chain  or 
bucket  elevator  should  be  constructed  to  convey  the  coal 
or  coke  to  the  scaffold  as  fast  as  it  is  shoveled  from  the  truck 
or  car.  Another  elevator  should  be  provided  for  pig  and  scrap 
iron,  and  as  the  iron  is  thrown  from  the  car  it  is  broken  and  at 
once  placed  upon  the  scaffold  convenient  for  melting.  This 
arrangement  saves  considerable  expense  for  labor  in  the  rehand- 
ling  of  iron  and  fuel,  and  also  prevents  the  loss  of  a  large  amount 
of  iron  and  fuel  annually  tramped  into  the  mud  in  the  yard  and 
lost.  The  saving  in  labor  and  stock  in  a  short  time  will  pay  the 
extra  expense  incurred  in  constructing  this  kind  of  scaffold. 

CUPOLA    FOUNDATION. 

Too  much  care  cannot  be  taken  in  putting  in  a  cupola  foun- 
dation, for  the  weight  of  a  cupola  and  stack,  when  lined  with 
fire-brick  to  the  top,  amounts  to  many  tons,  and  when  loaded 
with  fuel  and  iron  for  a  heat  to  many  tons  more.  If  the  foun- 
dation gives  way  and  the  cast  iron  cupola  bottom  is  broken  by 
uneven  settling,  the  cupola  is  rendered  practically  worthless,  for 
it  is  impossible  to  replace  the  bottom  with  a  new  one  without 


10  THE   CUPOLA   FURNACE. 

taking  out  the  entire  lining,  which  entails  much  expense,  and 
it  is  almost  impossible  to  bolt  or  brace  the  plate  so  as  to  keep 
it  in  place. 

The  foundation  should  be  built  of  solid  stone  work,  and  if  a 
good  foundation  cannot  be  had,  piles  must  be  driven.  Separate 
stone  piers  should  never  be  built  for  each  column  or  post,  for 
they  frequently  settle  unevenly  and  crack  the  bottom  plate. 
Uneven  settling  and  breaking  of  the  bottom  are,  to  a  large  ex- 
tent, prevented  by  placing  a  heavy  cast  iron  ring  upon  the 
stone  work  upon  which  to  set  the  cupola  supports.  This  ring 
should  be  placed  several  inches  below  the  floor  to  prevent  it 
being  warped  and  broken  by  the  heat  in  the  dump. 

When  brick  walls  are  constructed  for  the  support  of  a  cupola, 
trie  bottom  plate  is  made  square,  from  two  to  three  inches 
thick  and  strongly  ribbed  or  supported  by  railroad  iron  be- 
tween the  walls,  to  prevent  breaking.  The  walls  do  not  admit 
of  sufficient  freedom  in  removing  the  dump  and  for  this  reason 
are,  at  the  present  time,  seldom  used  in  the  construction  of  cu- 
polas. Even  when  the  cupola  is  set  so  low  that  a  pit  is  required 
for  the  removal  of  the  dump,  the  iron  supports  are  used  and  the 
pit  walls  built  outside  of  them.  When  the  round  cast  iron 
columns  are  employed,  the  plate  must  be  made  square  or  with  a 
projection  for  each  column,  to  admit  of  the  columns  being 
placed  at  a  sufficient  distance  apart  to  let  the  bottom  doors 
swing  between  them.  The  best  supports  for  a  cupola  are  the 
T-shaped  posts.  They  take  up  less  room  under  the  cupola  and 
are  less  in  the  way  when  removing  the  dump  than  the  round 
columns,  and  when  slightly  curved  at  the  top,  can  be  placed  at 
a  sufficient  distance  apart  to  permit  of  the  drop  doors  swinging 
between  them.  When  these  posts  are  used,  the  bottom  plate 
is  made  round,  and  of  only  a  slightly  larger  diameter  than  the 
cupola  shell  or  air  chamber,  and  when  made  of  good  iron  and 
the  foundation  plate  is  used,  the  bottom  plate  does  not  require  to 
be  more  than  I  y2  or  2  inches  thick  for  the  largest  sized  cupola. 
The  supports  when  curved  at  the  top  must  be  bolted  to  the 
plate  to  hold  them  in  place. 


CONSTRUCTING   A   CUPOLA.  II 

HEIGHT    OF   CUPOLA    BOTTOM. 

The  height  the  bottom  of  a  cupola  or  spout  should  be  placed 
above  the  moulding  floor  or  gangway,  depends  upon  the  class 
of  work  to  be  cast.  For  small  hand-ladle  work  the  proper 
height  is  18  to  20  inches;  for  small  bull-  and  hand-ladle  work 
24  to  30  inches ;  and  for  large  crane-ladle  work  three  to  five 
feet. 

It  is  very  difficult  and  dangerous  to  change  ladles  and  catch 
a  large  stream  from  a  high  cupola  in  hand-ladles ;  and  when 
pieces  are  only  cast  occasionally,  requiring  the  use  of  a  large 
crane-ladle,  it  is  better  to  place  the  cupola  low  and  dig  a  pit  in 
front  of  it,  in  which  to  set  the  ladle  when  a  large  one  is  re- 
quired for  the  work. 

When  the  cupola  is  set  low,  room  must  be  made  for  the  re- 
moval of  the  dump.  This  may  be  done  by  constructing  a  wall 
in  front  of  the  cupola  to  keep  up  the  floor  under  the  spout,  and 
lowering  the  floor  under  and  around  the  back  part  of  the 
cupola.  When  the  cupola  is  so  situated  that  this  can  not  be 
done,  a  pit  should  be  constructed  for  the  removal  of  the  dump. 

B01TOM   DOORS. 

For  cupolas  of"  small  diameter,  but  one  bottom  drop  door  is 
used.  But  when  the  cupola  is  of  large  diameter  the  door,  if 
made  in  one  piece,  would  be  so  large  that  there  would  not  be 
room  for  it  to  swing  clear  of  the  foundation  without  setting  the 
cupola  too  high,  and  the  door  would  be  very  heavy  and  difficult 
to  raise  into  place.  For  large  cupolas  the  door  is  cut  in  the 
middle  and  one-half  hung  to  the  bottom  on  each  side.  Four 
and  six  doors  are  sometimes  used,  but  they  are  always  in  the 
way  when  taking  out  the  dump,  and  require  more  care  in  put- 
ting in  place  and  supporting. 

The  doors  are  generally  made  of  cast  iron,  and  vary  in  thick- 
ness from  a  half-inch  to  an  inch  and  a  half  in  thickness,  and  are 
frequently  very  heavy  and  difficult  to  raise  into  place.  If  the 
doors  are  large  they  are  much  lighter  and  easier  to  handle 


12  THE   CUPOLA   FURNACE. 

when  made  of  wrought  iron,  and  if  properly  braced  answer 
the  purpose  equally  as  well  as  the  stiffer  cast  iron  one.  If  the 
lugs  on  the  bottom  plate  are  set  well  back  from  the  opening, 
and  the  lugs  on  the  doors  made  long,  the  doors  drop  further 
away  from  the  heat  of  the  dump,  and  may  be  swung  back  and 
propped  up  out  of  the  way  when  removing  the  dump. 

CASING. 

The  casing  or  shell  of  the  modern  cupola  and  stack  is  made 
of  iron  or  steel  boiler  plate,  riveted  together  with  one  or  two 
rows  of  rivets  at  each  seam.  The  thickness  of  the  plate  required 
depends  upon  the  diameter  and  height  of  the  cupola  and  stack. 
The  lining  in  the  stack  is  seldom  renewed,  while  the  lining  in 
the  cupola  is  often  removed  every  few  months  and  replaced 
with  a  new  one,  and  the  casing  must  be  of  a  sufficient  thickness 
to  support  the  stack  and  lining  when  the  cupola  lining  is  re- 
moved. The  strain  upon  the  casing  due  to  expansion  and 
shrinkage  is  not  very  great  when  properly  lined ;  but  when  im- 
properly lined  with  a  poor  quality  of  fire-brick,  the  expansion 
may  be  so  great  as  to  tear  apart  the  strongest  kind  of  casing. 
The  only  way  to  prevent  this  is  to  take  care  in  selecting  the 
fire-brick,  and  in  laying  up  the  lining.  The  greatest  wear  and 
tendency  to  rust  is  in  the  bottom  sheet,  and  it  is  also  weakened 
by  cutting  in  the  front,  tuyere  and  slag  holes,  and  should  be 
made  of  heavier  iron  than  any  other  part  of  the  casing.  Plate 
of  y±  inch  or  ^  inch  thickness  is  heavy  enough  for  almost  any 
sized  cupola.  The  cupola  and  stack  casing  are  generally  made 
in  one  piece,  the  cupola  ending  at  the  charging  door  and  the 
stack  beginning  at  the  same  point.  The  stack  may  be  con- 
tracted above  or  below  the  charging  door,  and  made  of  smaller 
diameter  than  the  cupola.  This  gives  a  better  draught  and 
requires  less  material  for  casing  and  lining ;  but  it  also  in- 
creases the  number  of  sparks  thrown  from  the  cupola  when  in 
blast.  Where  sparks  are  very  objectionable,  as  in  closely  built 
up  neighborhoods,  it  is  better  to  make  the  cupola  and  stack  of 
the  same  diameter,  or  to  enlarge  the  stack  from  the  bottom  of 


CONSTRUCTING  A    CUPOLA.  13 

the  charging  door.  This  may  be  done  by  placing  a  cast  iron 
•ring  upon  the  top  of  the  cupola  shell,  and  supporting  it  by 
brackets  riveted  to  the  shell,  and  placing  the  stack  shell  upon 
the  ring.  The  sparks  then  fall  back  into  the  cupola  if  the  stack 
is  of  a  good  height,  and  very  few  are  thrown  out  at  the  top. 

The  height  of  a  cupola  is  the  distance  from  the  top  of  the 
bottom  plate  to  the  bottom  of  the  charging  aperture.  Many 
plans  have  been  devised  for  utilizing  the  waste  heat  from  a 
cupola,  but  the  only  practical  means  so  far  discovered  is  to 
construct  a  high  cupola.  The  heat  lost  in  a  low  cupola  is  then 
utilized  in  heating  the  stock  in  the  cupola  before  it  escapes 
from  it.  But  all  the  heat  is  not  utilized  in  this  way,  for  a  great 
deal  of  gas  escapes  unconsumed.  This  is  shown  by  the  in- 
crease in  flame  as  the  stock  settles  in  the  cupola  to  a  point  at 
which  the  oxygen  from  the  charging  aperture  combines  with 
the  escaping  gas  in  sufficient  quantity  to  ignite  it,  when  it 
burns  with  a  fierce  flame  above  the  stock.  Still  a  great  deal 
more  heat  is  utilized  in  a  high  cupola  than  in  a  low  one. 

It  is  well  known  among  iron  founders  that  a  high  cupola  will 
melt  more  iron  in  a  given  time  and  with  less  fuel  than  a  low  one 
of  the  same  diameter.  Therefore  the  charging  aperture  should 
be  placed  at  the  highest  practicable  point.  There  is  a  limit  to 
the  height  at  which  the  aperture  in  a  small  cupola  can  be 
placed,  for  where  the  diameter  is  small  the  iron  in  settling  fre- 
quently lodges  against  the  lining  and  hangs  up  the  stock. 
When  this  occurs  the  stock  has  to  be  dislodged  by  a  long  bar 
worked  down  through  from  the  charging  aperture.  If  the 
aperture  is  placed  at  too  great  a  height  and  the  lodgment  takes 
place  near  the  bottom,  the  trouble  cannot  be  remedied  with  a 
bar,  and  melting  stops.  Cupolas  of  large  diameter  may  be 
made  of  almost  any  height  desired,  but  there  seems  to  be  a 
limit  to  the  height  at  which  heat  is  produced  in  a  cupola  by  the 
escaping  gases,  and  we  have  arranged  the  following  table  from 
practical  observation,  giving  the  approximate  height  and  size 
of  door  for  cupolas  of  different  diameters : 


14  THE   CUPOLA   FURNACE. 


Diameter 

Height  of 

Size  of  Charging 

Melting  Capacity 

Melting  Capacity 

Inside  Lining, 

Cupola, 

Door, 

per  Hour, 

per  Heat, 

Inches. 

Feet. 

Inches. 

Tons. 

Tons. 

18 

6-7 

15  x  18 

y±-% 

I  —  2 

20 

7-8 

18  x  20 

x—\ 

2—3 

24 

8-9 

20  X  24 

I  —  2 

3—5 

30 

9—12 

24  x  24 

2—5 

4  —  10 

40 

12  —  15 

30x36 

4-8 

8—20 

50 

I5—I8 

30x40 

6  —  14 

15—40 

60 

1  6  —  20 

3°X45 

8—  16 

25  —  60 

The  melting  capacity  of  a  cupola  varies  with  the  kind  of  fuel 
used.  One-fourth  more  iron  can  be  melted  per  hour  with  coke 
than  with  coal,  and  the  melting  capacity  per  heat  is  greatly  in- 
creased by  the  tapping  of  slag  and  number  of  tuyeres. 

CHARGING   DOOR. 

The  charging  door  may  be  made  in  one  or  two  sections  and 
lined  with  fire-brick  or  daubed  with  fire-clay;  or  it  may  be 
made  of  wire  gauze  placed  in  an  iron  frame.  The  charging 
door  is  of  but  little  importance  in  melting,  as  it  is  seldom 
closed  during  the  greater  part  of  the  heat,  and  is  only  of  service 
to  give  draught  to  the  cupola  when  lighting  up,  and  to  prevent 
sparks  being  thrown  upon  the  scaffold  during  the  latter  part  of 
the  heat. 

AIR   CHAMBER. 

The  air  chamber  for  supplying  the  tuyeres  with  blast  may  be 
constructed  either  outside  or  inside  the  cupola  shell.  When 
placed  inside,  the  cupola  must  be  boshed  and  the  lining  con- 
tracted at  the  bottom  to  make  room  for  the  chamber  without 
enlarging  the  diameter  of  the  cupola  casing.  When  the  cupola 
is  large  this  can  readily  be  done,  and  the  boshing  of  the  cupola 
increases  its  melting  capacity ;  but  small  cupolas  cannot  be 
contracted  at  the  bottom  to  a  sufficient  extent  to  admit  of  an 
air  chamber  being  placed  inside  without  interfering  with  the 
dumping  of  the  cupola.  When  placed  inside,  the  chamber  may 
be  formed  with  cast  iron  staves  made  to  rest  upon  the  bottom 
plate  at  one  end  and  against  the  casing  at  the  other.  The 


CONSTRUCTING  A   CUPOLA.  15 

staves  are  flanged  to  overlap  each  other  with  a  putty  joint,  and 
.when  new  make  a  very  nice  air  chamber.  But  when  the  lining 
becomes  thin  they  become  heated  and  frequently  warp  or 
break,  and  permit  the  blast  to  escape  through  the  lining  to  so 
great  an  extent  that  the  lining  has  to  be  removed  and  the 
staves  replaced  with  new  ones. 

The  air  chamber,  when  constructed  inside  the  casing,  should 
be  made  of  boiler  plate,  and  securely  riveted  to  the  casing  to 
hold  it  in  place  and  prevent  leakage  of  blast  through  the  lining. 
It  must  be  constructed  of  a  form  to  correspond  with  the  bosh- 
ing of  the  cupola,  and  of  a  size  to  supply  a  sufficient  quantity 
of  blast  to  all  the  tuyeres.  If  these  conditions  cannot  be  met 
without  reducing  the  cupola  below  40  inches  diameter  at  the 
tuyeres,  then  the  air  chamber  should  be  placed  on  the  outside, 
and  any  desired  boshing  of  the  cupola  made  by  placing  com- 
mon red  brick  behind  the  fire-brick  lining. 

When  the  air  chamber  is  placed  upon  the  outside  of  the 
shell,  it  may  be  formed  by  a  round  cast  iron  or  sheet  metal 
pipe  extending  around  the  cupola,  with  branches  extending 
down  to  each  tuyere ;  or  it  may  be  made  of  boiler  plate  and 
riveted  to  the  shell.  The  great  objection  to  the  round  or  over- 
head air  chamber  is  the  numerous  joints  required  in  connecting 
it  with  each  tuyere.  These  joints  require  continual  looking 
after  to  prevent  leakage  of  blast,  and  in  many  cases  they  are 
not  examined  from  one  year's  end  to  another,  and  a  large  per 
cent,  of  the  blast  is  frequently  lost  through  leaky  joints.  The 
best  air  chambers  are  those  made  of  boiler  plate  and  riveted  to 
the  cupola  shell  and  securely  corked.  These  air  chambers 
are  made  of  any  shape  that  may  suit  the  fancy  of  the  construc- 
tor, and  in  many  cases  are  very  much  in  the  way  of  the  melter 
in  making  up  the  cupola  and  of  the  moulders  in  removing  the 
molten  iron.  They  should  not  be  made  to  extend  out  from  the 
shell  more  than  six  inches,  and  any  air  capacity  desired  given 
by  extending  the  chamber  up  or  down  the  shell.  The  air 
capacity  should  not  be  less  than  three  or  four  times  the  area  of 
the  outlet  of  the  blower,  and  may  be  much  larger.  The  blast 


1 6  .  THE   CUPOLA   FURNACE. 

should  be  admitted  to  the  chamber  from  the  top  on  each  side 
of  the  cupola.  This  arrangement  places  the  pipes  out  of  the 
way  where  they  are  least  likely  to  be  knocked  and  injured. 
When  the  tuyeres  are  placed  low,  the  chamber  may  be  made 
to  extend  down  to  the  bottom  plate.  In  this  case,  the  bottom 
plate  must  be  made  larger  and  the  chamber  cut  away  front  and 
back  for  the  tap  and  slag  holes. 

When  the  tuyeres  are  placed  high,  the  chamber  should  be 
placed  up  out  of  the  way  of  the  tap  and  slag  holes,  and  riveted 
to  the  shell  at  both  top  and  bottom.  An  opening  should  be 
made  in  the  air  chamber  under  each  tuyere  and  covered  with  a 
piece  of  sheet  lead,  so  that  any  molten  iron  or  slag  running  into 
the  chamber  from  the  tuyeres  will  flow  out  and  not  injure  or 
fill  up  the  chamber.  An  opening  should  be  placed  in  front  of 
each  tuyere  for  giving  draught  to  the  cupola  when  lighting  up, 
and  for  the  removal  of  any  iron  or  slag  that  may  run  into  the 
tuyere  during  a  heat.  These  openings  should  not  be  made 
over  three  or  four  inches  in  diameter,  and  should  each  be  pro- 
vided with  a  tight-fitting  door  to  prevent  the  escape  of  the  blast. 

TAP   HOLE. 

One  or  more  orifices  are  placed  in  the  casing  at  the  bottom 
plate  for  the  removal  of  the  molten  iron  from  the  cupola. 
These  openings  are  known  as  tap  holes,  and  in  the  casing  are 
from  six  to  eight  inches  wide  and  seven  to  nine  inches  high, 
curved  or  rounded  at  the  top.  The  opening  through  the 
cupola  lining  is  generally  formed  by  the  brick  and  presents  a 
very  ragged  appearance  after  the  lining  has  been  in  use  a  short 
time.  This  opening  should  be  lined  with  a  cast  iron  casting 
bolted  to  the  cupola  casing,  and  made  to  extend  almost 
through  the  lining.  The  casing  should  be  made  slightly  taper- 
ing with  the  large  end  inside,  or  ribbed,  to  prevent  the  front 
being  pushed  out  by  the  pressure  of  molten  iron  retained  in 
the  cupola.  For  small  cupolas,  or  a  large  cupola  from  which 
the  iron  is  removed  in  large  ladles,  but  one  tap  hole  is  required. 
But  large  cupolas  melting  over  eight  tons  of  iron  per  hour, 


CONSTRUCTING  A   CUPOLA.  1 7 

from  which  the  iron  is  taken  in  hand  ladles,  require  two  tap 
holes.  Two  tap  holes  are  sometimes  placed  in  a  cupola  on 
opposite  sides  to  shorten  the  distance  of  carrying  the  iron  to 
the  moulds.  And  two  tap  holes  are  also  sometimes  placed 
side  by  side  so  that  each  may  be  kept  in  better  order  through 
the  heat.  This  is  bad  practice,  for  if  the  front  is  properly  put 
in,  one  tap  hole  will  run  off  all  the  iron  a  cupola  is  capable  of 
melting.  When  two  tap  holes  are  put  in  they  should  be  placed 
one  in  front  and  the  other  in  the  back  or  side  of  the  cupola,  so 
that  the  moulders  will  not  be  in  each  other's  way  when  catch- 
ing-in. 

THE  SPOUT. 

A  short  spout  must  be  provided  for  conveying  the  molten 
iron  from  the  tap  hole  to  the  ladles.  This  spout  is  generally 
made  of  cast  iron,  and  is  from  six  to  eight  inches  wide  with 
sides  from  three  to  six  inches  high,  and  for  small  ladle  work  is 
from  one  to  two  feet  long.  For  large  ladle  work  it  is  made 
much  longer.  In  some  foundries  where  a  long  spout  is  only 
occasionally  required,  the  spout  is  made  in  two  sections  and 
put  together  with  cleats,  so  that  an  additional  section  may  be 
put  up  to  fill  a  large  ladle  and  taken  down  when  it  is  fillgd.  The 
spout  should  be  long  enough  to  throw  the  stream  near  the 
center  of  the  ladle  when  filling.  In  a  great  many  foundries 
the  spout  is  laid  upon  the  bottom  plate,  and  only  held  in  place 
by  the  making  up  of  the  front,  and  is  removed  after  each  heat. 
This  entails  the  loss  of  a  great  deal  of  spout  material  each  heat, 
and  sometimes  the  spout  is  struck  in  the  careless  handling  of 
ladles  and  knocked  out  of  place,  when  much  damage  may  be 
done.  When  not  in  the  way  of  removing  the  dump,  the  spout 
should  be  securely  bolted  to  the  bottom  plate. 

When  it  is  desired  to  run  a  very  small  cupola  for  a  greater 
length  of  time  than  an  hour  and  a  half,  or  a  large  cupola  for  a 
longer  time  than  two  hours  and  a  half,  slag  must  be  tapped  to 
remove  the  ash  of  the  fuel  and  dross  of  the  iron  from  the 
cupola,  to  prevent  bridging  over  and  bunging  up.  The  slag 
2 


1 8  THE   CUPOLA   FURNACE. 

hole  from  which  the  slag  is  tapped  is  placed  between  the 
tuyeres,  and  below  the  lower  level  of  the  lower  row  of  tuyeres. 
A  hole  is  cut  through  the  casing  and  lining  from  three  to  four 
inches  in  diameter,  and  a  short  spout  or  apron  is  provided  to 
carry  the  slag  out,  so  that  it  will  fall  clear  of  the  bottom  plate. 
The  slag  hole  should  be  placed  at  the  back  of  the  cupola,  or  at 
the  greatest  possible  distance  from  the  tap  hole,  so  that  the 
slag  will  not  be  in  the  way  of  the  moulders  when  catching  the 
iron.  The  height  at  which  a  slag  hole  should  be  placed  above 
the  sand  bottom  depends  upon  how  the  iron  is  tapped.  The 
slag  in  a  cupola  drops  to  the  bottom  and  floats  upon  the  sur- 
face of  the  molten  metal,  and  rises  and  falls  with  it  in  the 
cupola.  If  the  molten  iron  is  held  in  the  cupola  until  a  large 
body  accumulates,  the  slag  hole  must  be  placed  high  and  the 
slag  tapped  when  it  has  risen  upon  the  surface  of  the  molten 
iron  to  the  slag  hole.  When  the  iron  is  withdrawn,  the  slag 
remaining  in  the  cupola  falls  below  the  slag  hole,  and  the  hole 
must  be  closed  with  a  bod  to  prevent  the  escape  of  blast.  If 
the  iron  is  drawn  from  the  cupola  as  fast  as  melted,  the  slag 
hole  is  placed  two  or  three  inches  above  the  sand  bottom  at  the 
back  of  the  cupola.  The  slag  then  lies  upon  the  molten  iron, 
or  upon*the  sand  bottom,  and  the  slag  hole  may  be  opened  as 
soon  as  slag  has  formed,  and  allowed  to  remain  open  through- 
out the  heat. 

TUYERES. 

A  number  of  openings  are  made  through  the  casing  and  lin- 
ing near  the  bottom  of  the  cupola  for  admitting  the  blast  into 
the  cupola  from  the  air  chamber  or  blast  pipe.  These  open- 
ings are  known  as  tuyeres.  Tuyeres  have  been  designed  of  all 
shapes  and  sizes,  and  have  been  placed  in  cupolas  in  almost 
every  conceivable  position,  so  there  is  little  to  be  learned  by 
experimenting  with  them,  and  the  only  things  to  be  considered 
are  the  number,  shape,  size  and  position  of  tuyeres  for  different 
sized  cupolas.  For  a  small  cupola,  two  tuyeres  are  sufficient. 
A  greater  number  promotes  bridging.  They  should  be 


CONSTRUCTING   A   CUPOLA.  19 

placed  in  the  cupola  on  opposite  sides,  so  that  the  blast  will 
•meet  in  the  center  of  the  cupola,  and  not  be  thrown  against  the 
lining  at  any  one  point  with  great  force.  The  best  shape  for  a 
small  cupola  is  a  triangular  or  upright-slot  tuyere.  These 
cause  less  bridging  than  the  flat-slot  or  oval  tuyere,  and  in 
small  cupolas  make  but  little  difference  in  the  amount  of  fuel 
required  for  the  bed.  When  only  two  tuyeres  are  provided,  a 
belt  air  chamber  around  the  cupola  is  not  required,  and  the 
blast  pipes  are  generally  connected  direct  with  each  tuyere. 
In  large  cupolas,  the  shape  of  the  tuyeres  selected  makes  but 
little  difference  in  the  melting,  so  long  as  they  are  of  sufficient 
size  and  number  to  admit  the  proper  amount  of  blast  to  the 
cupola,  and  so  arranged  as  to  distribute  it  evenly  to  the  stock. 
The  flat-slot  or  oval  tuyeres  are  generally  selected  for  the 
reason  that  they  require  less  bed  than  the  upright-slot  tuyere. 

The  number  of  tuyeres  required  varies  from  four  to  eight, 
according  to  the  size  of  the  cupola  and  tuyeres.  They  should 
be  of  the  same  size  and  placed  at  uniform  distances  apart.  A 
tuyere  should  never  be  placed  directly  over  the  tap  or  slag  hole. 
The  combined  tuyere  area  should  be  from  two  to  three  times 
greater  than  the  area  of  the  blower  outlet.  The  tuyere  boxes 
or  casings  are  made  of  cast  iron,  and  should  be  bolted  to  the 
cupola  shell  to  prevent  any  escape  of  blast  through  the  lining 
when  it  becomes  old  and  shaky,  or  when  lined  with  poor 
material  and  the  grouting  works  out,  as  is  sometimes  the  case. 

The  height  at  which  tuyeres  are  placed  in  cupolas  above  the 
sand  bottom  varies  from  one  or  two  inches  to  five  feet,  and 
there  is  a  wide  difference  of  opinion  among  founders  as  to  the 
height  at  which  they  should  be  placed.  '  When  the  tuyeres  are 
placed  low,  the  iron  must  be  drawn  from  the  cupola  as  fast  as 
melted,  to  prevent  it  running  into  the  tuyeres.  In  foundries 
where  the  iron  is  all  handled  in  hand-ladles,  this  can  readily  be 
done,  and  the  tuyeres  are  placed  low  to  reduce  the  quantity  of 
fuel  in  the  bed  and  make  hot  iron.  In  foundries  in  which 
heavy  work  is  cast,  and  the  iron  handled  in  large  ladles,  the 
tuyeres  are  placed  high,  so  that  a  large  amount  of  iron  may  be 


20  THE   CUPOLA   FURNACE. 

accumulated  in  the  cupola  to  fill  a  large  ladle  for  a  heavy  piece 
of  work. 

We  do  not  believe  in  high  tuyeres,  and  claim  they  should 
never  be  placed  more  than  10  or  12  inches  above  the  sand 
bottom  for  any  kind  of  work ;  and  if  slag  is  not  to  be  tapped 
from  the  cupola,  they  should  not  be  placed  more  than  two  or 
three  inches  above  the  sand  bottom.  In  stove  foundries,  in 
which  cupolas  of  large  diameter  are  employed  and  hot  iron  re- 
quired throughout  the  heat,  the  tuyeres  are  placed  so  low  that 
the  sand  bottom  is  made  up  to  within  one  inch  of  the  bottom 
of  the  tuyeres  on  the  back,  and  two  or  three  inches  at  the  front. 
This  gives  plenty  of  room  below  the  tuyeres  for  holding  iron 
without  danger  of  it  running  into  the  tuyeres.  In  cupolas  of 
small  diameter,  two  inches  is  allowed  at  the  back  and  three  or 
four  inches  at  the  front.  This  insures  a  hot,  even  iron  through- 
out the  heat,  if  the  cupola  is  properly  charged,  and  a  much  less 
quantity  of  fuel  is  required  for  the  bed  than  if  the  tuyeres  were 
placed  high.  Molten  iron  is  never  retained  in  the  cupola  for 
this  class  of  work,  and  the  tap  hole  is  made  of  a  size  to  let  the 
iron  out  as  fast  as  melted  and  the  stream  kept  running  through- 
out the  heat. 

Cupolas  with  high  tuyeres  are  not  employed  for  this  class  of. 
work,  for  they  do  not  produce  a  hot  fluid  iron  throughout  a 
heat  without  the  use  of  an  extraordinarily  large  per  cent,  of 
fuel,  and  when  the  tuyeres  are  extremely  high  they  do  not 
make  a  hot  iron  with  any  amount  of  fuel.  Nothing  is  gained 
by  holding  molten  iron  in  a  cupola,  for  iron  can  be  kept  hotter 
in  a  ladle  than  in  a  cupola,  and  melted  hotter  with  low  than 
high  tuyeres,  and  a  cupola  is  kept  in  better  melting  condition 
throughout  a  heat  by  tapping  the  iron  as  fast  as  melted. 

TWO  OR  MORE  ROWS  OF  TUYERES. 

It  is  the  common  practice  to  place  all  the  tuyeres  in  a  cupola 
at  the  same  level,  or  in  one  row  extending  around  the  cupola. 
But  two  or  more  rows  are  frequently  placed  one  above  the 
other.  When  a  large  number  of  rows  are  employed,  they 


CONSTRUCTING   A   CUPOLA.  21 

decrease  in  area  gradually  from  the  lower  to  the  top  tuyere, 
and  the  rows  are  generally  placed  very  close  together.  When 
two  rows  are  put  in,  the  second  row  is  made  from  one-half  to 
one-tenth  the  area  of  the  first  row,  and  the  two  rows  are  placed 
from  8  to  1 8  inches  apart.  If  the  area  of  the  second  row  is 
one-half  that  of  the  first,  it  is  generally  placed  from  8  to  10 
inches  above  the  first  row,  and  only  when  the  tuyeres  are  very 
small  are  they  placed  at  a  greater  height  above  the  first  row. 
When  three  rows  are  put  in,  the  second  row  is  made  one-half 
the  area  of  the  first  row,  and  the  third  row  one-fourth  the  area 
of  the  second,  and  the  rows  are  placed  from  6  to  10  inches 
apart.  When  tuyeres  are  placed  in  a  cupola  all  the  way  up 
to  the  charging  door,  those  above  the  first  or  second  rows  are 
made  one  inch  diameter,  and  are  placed  from  12  to  14  inches 
above  each  other. 

The  tuyere  in  the  upper  row  may  be  placed  directly  over  the 
tuyere  in  the  row  beneath  it,  or  may  be  placed  between  two 
lower  ones.  Some  cupola  men  claim  that  much  better  results 
are  obtained  by  this  latter  plan,  but  we  have  never  observed  that 
it  made  any  difference  whether  they  were  placed  over  or  be- 
tween those  of  the  lower  rows. 

Faster  melting  is  secured  with  two  or  three  rows  of  tuyeres 
than  with  one  row  in  cupola  of  the  same  diameter,  and  the 
melting  capacity  per  hour  is  increased  about  one-fourth  in 
melting  large  heats.  When  melting  a  small  heat  for  the  size  of 
the  cupola,  nothing  is  gained  by  the  additional  rows  of  tuyeres, 
since  a  much  larger  quantity  of  fuel  is  required  in  the  bed,  for 
which  there  is  no  recompense  by  saving  of  fuel  in  the  charges 
through  the  heat,  and  fast  melting  is  seldom  any  great  object 
in  small  heats. 

LINING. 

The  casing  may  be  lined  with  fire-brick,  soapstone  or  other 
refractory  substances.  In  localities  where  fire-brick  cannot  be 
obtained,  native  refractory  materials  are  used;  but  fire-brick 
are  to  be  preferred  to  native  mineral  substances.  Cupola  brick 


22  THE    CUPOLA   FURNACE. 

are  now  made  of  almost  any  shape  or  size  required  in  cupola 
lining,  and  can  be  purchased  at  as  reasonable  a  price  as  the 
common  straight  fire-brick.  The  curved  brick,  laid  flat,  make 
a  more  compact  and  durable  lining  than  the  wedge-shaped 
brick  set  on  end,  and  are  most  generally  used.  When  laying 
up  a  lining,  the  grouting  or  mortar  used  should  be  of  the  same 
refractory  material  as  the  brick,  so  that  it  will  not  burn  out  and 
leave  crevices  between  the  brick,  into  which  the  flame  pene 
trates  and  burns  away  the  edges  of  the  brick.  This  material  is 
made  into  a  thin  grout,  and  a  thin  layer  is  spread  upon  the 
bottom  plate.  The  brick  is  then  taken  in  the  hand,  one  end 
dipped  in  the  grout,  and  laid  in  the  grout  upon  the  plate. 
When  a  course  or  circle  has  been  laid  up,  the  top  is  slushed 
with  grout  to  fill  up  all  the  cracks  and  joints,  and  the  next 
course  is  laid  up  and  grouted  in  the  same  way.  The  joints  are 
broken  at  each  course,  and  the  brick  are  laid  close  together  to 
make  the  crevice  between  them  as  small  as  possible,  and  pre- 
vent the  flame  burning  away  the  corners  in  case  the  grouting 
material  is  not  good  and  burns  out. 

Brick  that  do  not  expand  when  heated  are  laid  close  to  the 
casing.  Those  that  do  expand  are  laid  from  a  fourth  of  an 
inch  to  an  inch  from  the  casing,  to  give  room  for  expansion, 
and  the  space  is  filled  in  with  sand  or  grout.  Brick  of  un- 
known properties  should  always  be  laid  a  short  distance  from 
the  casing,  to  prevent  it  being  burst  by  expansion  of  the 
lining. 

The  lining  is  made  of  one  thickness  of  brick,  and  a  brick  is 
selected  of  a  size  to  give  the  desired  thickness  of  lining.  In 
small  cupolas,  a  four  or  five-inch  lining  is  used,  and  in  large 
cupolas  a  six  or  nine-inch  lining.  A  heavier  lining  than  nine 
inches  is  seldom  put  in,  except  to  reduce  the  diameter  of  the 
cupola  or  prevent  the  heating  of  the  shell.  In  these  cases,  a 
filling  or  false  lining  of  common  red  brick  is  put  in  between  the 
fire-brick  and  shell.  The  stack  lining  is  seldom  made  heavier 
than  four  inches  for  any  sized  cupola,  as  the  wear  upon  it 
is  not  very  great,  and  a  four-inch  lining  lasts  for  a  number  of 


CONSTRUCTING   A   CUPOLA.  23 

years.     The   stack  lining  is  laid  up  and  grouted  in   the   same 
way  as  the  cupola  lining. 

ARRANGEMENT   OF    BRACKETS,    ETC. 

In  Fig.  I  is  shown  the  manner  in  which  brackets  or  angle 
iron  are  put  into  a  cupola  for  the  support  of  the  lining  in  sec- 
tions upon  the  casing.  The  brackets  are  made  of  heavy  boiler 
plate  from  five  to  six  inches  wide,  circled  to  fit  the  casing  and 

FIG.  i. 


SECTIONAL  VIEW   OF  CUPOLA. 


bent  at  a  square  angle.     The  part  riveted  to  the  casing  is  made 
four  inches  long  and  secured  to  the  casing  with  two  or  three 


24  THE   CUPOLA   FURNACE. 

rivets.  The  bracket  or  shelf  for  the  support  of  the  lining  is 
made  from  one  and  a  half  to  two  inches  long.  The  brackets 
are  placed  about  two  feet  apart  around  the  casing  and  in  rows 
from  two  to  three  feet  above  each  other.  These  brackets  are 
but  little  in  the  way  when  laying  up  a  lining,  and  support  the 
latter  so  that  a  section  may  be  taken  out  and  replaced  without 
disturbing  the  remainder  of  the  lining. 

Angle  iron  is  by  many  preferred  to  brackets  for  the  support 
of  the  lining.  It  is  put  in  bands  extending  all  the  way  around 
the  casing  and  riveted  to  it.  These  bands  not  only  support  the 
lining  but  act  as  a  brace  to  the  casing,  and  in  some  respects  are 
a  better  support  for  the  lining  than  brackets.  They  catch  and 
hold  in  place  all  the  grouting  or  sand  that  may  work  out  of  the 
lining  between  the  casing,  and  give  a  more  even  support  to  the 
lining,  but  with  their  use  it  is  sometimes  more  difficult  to  fit  the 
brick  around  when  laying  up  a  lining.  Still,  angle  iron  has  gener- 
ally taken  the  place  of  brackets  and  is  put  in  all  the  modern 
cupolas.  The  brackets  or  angle  iron  should  not  be  made  to 
extend  out  from  the  casing  more  than  one  and  a  half  or  two 
inches,  for  if  they  do  they  are  liable  to  be  burned  off  when  the 
lining  becomes  thin  and  let  the  iron  or  heat  through  to  the  cas- 
ing. One  and  a  half  inches  are  sufficient  to  support  the  lining 
if  the  brick  form  a  circle  to  fit  the  casing.  No  supports  should 
be  put  in  at  the  melting  zone,  for  the  lining  frequently  burns 
very  thin  at  this  point,  even  in  a  single  heat.  It  is  not  necessary 
to  put  in  any  below  the  melting  zone,  and  the  first  one  should 
be  placed  at  the  upper  edge  of  the  zone,  and  from  this  up  they 
should  be  put  in  at  every  two  or  three  feet. 

The  weight  of  brick  placed  upon  the  lower  courses  in  a 
cupola  lining  is  sufficient  to  crush  most  of  the  soft  cupola  brick, 
and  were  it  not  for  the  support  given  to  three  sides  of  them  in 
the  lining  they  would,  by  the  great  weight  placed  upon  them, 
be  reduced  to  a  powder.  As  a  lining  burns  out  it  becomes 
thin  more  rapidly  at  the  bottom,  and  it  often  happens  that  the 
lining  at  the  melting  zone  is  reduced  to  one-half  its  thickness, 
or  even  less,  in  a  few  heats,  and  this  reduced  lining  often  has  to 


CONSTRUCTING  A   CUPOLA.  25 

support  a  lining  of  almost  full  thickness  for  the  entire  cupola, 
and  in  some  cases  also  the  stack  lining.  The  cohesive  force  of 
these  bricks  is  reduced  by  the  intense  heat  in  the  cupola,  and 
when  subjected  to  so  great  a  pressure  and  heated  they  are 
crushed  and  the  lining  gradually  settles  and  becomes  shaky. 
This  settling  is  so  great  with  some  qualities  of  brick  that  in 
cupolas  having  no  frame  riveted  to  the  casing  around  the 
charging  aperture,  the  arch  over  the  door  frequently  settles  so 
low  that  it  becomes  necessary  to  rebuild  it  to  maintain  the  full 
size  of  the  opening. 

Brick  do  not  give  the  best  results  when  subjected  to  so  great 
a  pressure  and  heated  to  a  high  temperature.  Therefore,  in  all 
cupolas,  brackets  or  angle  iron  should  be  put  in  every  two  or 
three  feet  for  the  support  of  the  lining  on  the  casing,  and  the 
casing  should  be  made  heavy  enough  to  support  the  entire 
lining  when  a  section  has  been  burned  out  or  removed. 

In  the  illustration  (Fig.  I )  is  also  shown  a  way  for  reducing  the 
size  and  weight  of  the  bottom  doors  and  preventing  the  casing 
from  rusting  off  at  the  bottom.  In  many  of  the  large  cupolas  re- 
quiring heavy  sand  bottoms,  the  bottom  plate  can  be  made  to 
extend  into  the  cupola  from  three  to  six  inches  all  round  with- 
out in  the  least  interfering  with  dumping,  and  the  first  few 
courses  of  brick  sloped  back  from  the  edge  of  the  plate  to  the 
regular  thickness  of  lining  to  prevent  sand  lodging  on  the  edges 
of  the  plate  around  the  lining.  By  this  arrangement  in  large 
cupolas  the  diameter  of  the  doors  may  be  reduced  from  six  to 
ten  inches  and  very  much  lightened,  and  less  sand  will  be  re- 
quired, for  the  sand  bottom  and  the  dump  falls  as  freely  as 
when  the  doors  are  the  full  size  of  the  cupola. 

Cupolas  that  are  not  in  constant  use  absorb  a  great  deal  of 
moisture  into  the  lining  and  are  constantly  wet  around  the 
bottom  plate,  and  light  casings  are  eaten  away  by  rust  in  a 
short  time.  To  prevent  this  the  first  one  or  two  courses  of 
brick  can  be  laid  a  few  inches  from  the  casing  and  a  small  air 
chamber  formed  around  the  cupola  at  this  point.  If  this 
chamber  is  supplied  with  air  from  a  few  small  holes  through 


26  THE   CUPOLA   FURNACE. 

the  iron  bottom  or  casing,  the  latter  is  kept  dry  and  rusting 
is  prevented. 

In  the  illustration  (Fig.  i)  is  shown  the  triangular-shaped 
tuyere  in  position  in  the  lining.  This  tuyere  prevents  bridging 
to  a  greater  extent  than  any  other,  and  is,  for  a  small  cupola, 
one  of  the  very  best  shapes.  It  is  formed  with  a  cast  iron 
frame  set  in  the  lining,  and  each  tuyere  may  be  connected  with 
a  separate  pipe,  as  shown,  or  they  may  be  connected  with  an 
air  belt  extending  around  the  cupola. 

Bottom  plates  may  be  cast  with  a  light  flange  around  the 
edge,  as  shown  in  the  illustration  (Fig.  i),  or  made  perfectly 
flat  on  top ;  but  it  is  better  to  cast  them  with  a  small  flange  or 
bead  for  holding  the  shell  in  place  upon  the  plate,  and  thus 
cause  the  cupola  to  have  a  more  finished  look  around  the 
bottom. 

FIRE   PROOF    SCAFFOLDS. 

The  charging  door  or  opening  through  which  fuel  and  iron 
are  charged  into  a  cupola  is  placed  at  so  great  a  height  from 
the  floor  that  it  is  necessary  to  construct  a  platform  or  scaffold, 
upon  which  to  place  the  stock,  and  from  which  to  charge  it 
into  the  cupola.  For  heavy  work,  this  scaffold  is  generally 
placed  on  three  sides  of  the  cupola,  leaving  the  front  clear  for 
the  swinging  of  crane  ladles  to  and  from  the  spout ;  but  for 
light  work  the  scaffold  frequently  extends  all  the  way  around 
the  cupola  to  give  more  room  for  placing  stock  upon  it.  The 
distance  the  floor  of  a  scaffold  is  generally  placed  below  the 
charging  door  is  about  two  feet,  but  that  distance  varies,  and 
floors  are  frequently  placed  on  a  level  with  the  door  or  three 
or  four  feet  below  it  to  suit  the  kind  of  iron  to  be  melted  or  the 
facilities  for  placing  stock  upon  the  scaffold  from  the  yard. 
The  scaffold  and  its  supports  are  more  exposed  to  fire  than 
almost  any  other  part  of  a  foundry,  for  live  sparks  are  thrown 
from  the  charging  door  upon  the  scaffold  floor,  and  molten 
iron,  slag,  etc.,  are  frequently  thrown  against  its  supports  and 
the  under  side  of  the  floor  with  considerable  force  when  dump- 


CONSTRUCTING   A   CUPOLA.  2J 

ing  the  cupola.  Numerous  plans  have  been  devised  to  make 
scaffolds  fire-proof  and  prevent  the  foundry  from  being 
set  on  fire.  In  many  of  the  wooden  foundry  buildings 
the  scaffold  is  constructed  entirely  of  wood,  and  to  render 
it  fire-proof  the  supports  and  under  side  of  the  floor  are 
covered  with  light  sheet  iron  to  protect  them  from  molten 
iron,  slag,  etc.,  when  dumping.  The  covering  of  the  wood- 
work of  a  scaffold  in  this  way  is  very  bad  practice,  for  while 
it  protects  the  wood  from  direct  contact  with  the  fire,  it 
also  prevents  it  from  being  wetted,  and  in  a  short  time  the 
wood  becomes  very  dry  and  very  combustible.  The  thin 
covering  of  sheet  iron  is  soon  eaten  away  with  rust,  leaving 
holes  through  which  sparks  may  pass  and  come  in  contact  with 
the  dry  wood  and  ignite  it  under  the  sheet  iron  where  it  cannot 
be  seen,  and  the  cupola  men,  after  wetting  down  the  dump  very 
carefully,  may  go  home  leaving  a  smoldering  fire  concealed  by 
the  sheet  iron  covering  which  may  break  forth  during  the  night 
and  destroy  the  foundry.  It  is  better  to  leave  all  the  wood- 
work entirely  uncovered  and  exposed  to  the  fire  and  heat,  and 
wet  it  in  exposed  places  before  and  after  each  heat ;  the  wood 
is  then  kept  dampened  and  is  not  so  readily  combustible  as 
when  covered  with  sheet  iron,  and  if  ignited  the  fire  may  be 
seen  and  extinguished  before  the  men  leave  for  home  after  their 
day's  work  is  done.  At  many  of  the  wooden  foundry  buildings 
the  cupola  is  placed  outside  the  foundry  building  and  a  small 
brick  house  or  room  constructed  for  it  and  the  molten  iron  run 
into  the  foundry  by  a  cupola  spout  extending  through  the  wall. 
In  this  way  a  scaffold  may  be  made  entirely  fire-proof  by  put- 
ting in  iron  joist  and  an  iron  or  brick  floor,  and  putting  on  an 
iron  roof.  We  saw  a  scaffold  and  cupola  house  at  a  small  foundry 
in  Detroit,  Mich.,  about  twenty  years  ago,  that  was  constructed 
upon  a  novel  plan  and  was  perfectly  fire-proof.  The  house  was 
twelve  feet  square  and  constructed  of  brick,  the  scaffold  floor 
was  of  iron  and  supported  by  iron  joist,  the  walls  were  perpen- 
dicular to  five  feet  above  the  scaffold  floor,  and  from  this  point 
they  were  contracted  and  extended  up  to  a  sufficient  height  to 


28  THE   CUPOLA   FURNACE. 

form  a  stack  three  feet  square  at  the  top.  The  cupola  was  placed 
at  one  side  of  this  room  and  the  cupola-house,  and  the  spout 
extended  through  the  wall  into  the  foundry;  the  open  top  of  the 
cupola  extended  about  two  feet  above  the  scaffold  floor,  and  its 
stack  was  formed  by  the  contracted  walls  of  the  cupola-house. 
There  were  no  windows  in  the  house,  and  only  one  opening 
above  for  placing  stock  upon  the  scaffold  and  one  below  for  re- 
moving the  dump  and  making  up  the  cupola,  both  of  which 
openings  were  fitted  with  iron  door  frames  and  doors,  and 
could  be  tightly  closed.  When  lighting  up,  the  scaffold  door 
was  closed  to  give  draught  to  the  cupola,  and  when  burned  up 
the  door  was  opened  and  the  cupola  charged  from  the  scaffold. 
Sparks  from  the  cupola  when  in  blast  fell  upon  the  scaffold 
floor  and  were  never  thrown  from  the  top  of  the  stack  or  cupola- 
house  upon  the  foundry  roof  or  the  roofs  of  adjoining  build- 
ings, and  when  the  doors  were  closed  the  scaffold  was  as  fire- 
proof as  a  brick  stack.  The  great  objection  to  this  scaffold  was 
the  gas  from  the  cupola  upon  the  scaffold  when  the  blast  was 
on,  and  the  intense  heat  upon  the  scaffold  in  warm  weather  or 
when  the  stock  got  low  in  the  cupola. 

The  best  and  safest  scaffolds  are  those  constructed  entirely 
of  iron,  or  with  brick  floors  and  supported  by  iron  columns,  or 
brick  walls  and  made  of  a  sufficient  size  to  admit  of  wood  or 
other  readily  combustible  cupola  material  being  placed  at  a  safe 
distance  from  the  cupola.  The  cupola  scaffold  in  the  foundry 
of  Gould  &  Eberhardt,  Newark,  N.  J.,  is  constructed  of  iron 
supported  by  iron  columns  and  brick  walls,  and  is  of  sufficient 
size  and  strength  to  carry  two  car-loads  of  coke,  one  hundred 
tons  of  pig  and  scrap  iron,  and  all  the  wood  shavings  and  other 
material  required  for  the  cupola.  In  the  new  iron  foundry 
building  recently  erected  by  The  Straight  Line  Engine  Com- 
pany, Syracuse,  N.  Y.,  the  scaffold  is  constructed  entirely  of  iron 
and  supported  by  the  iron  columns  which  support  the  foundry 
roof.  It  extends  the  entire  length  of  the  foundry,  affording 
ample  room  for  storing  iron,  coke,  wood,  and  all  cupola  sup- 
plies, thus  doing  away  with  a  yard  for  storing  such  material,  and 


CONSTRUCTING  A   CUPOLA.  2Q 

placing  them  under  the  foundry  roof  and  convenient  for  use. 
Scaffolds  of  this  kind  greatly  reduce  the  expense  of  handling 
cupola  stock,  and  also  reduce  the  rate  of  insurance  of  foundry 
buildings. 


CHAPTER  III. 

CUPOLA  TUYERES. 

THE  cupola  furnace  may  be  supplied  with  the  air  required 
for  the  combustion  of  the  fuel  by  natural  draft  induced  by  a 
high  stack,  a  vacuum  created  by  a  jet  of  steam,  or  by  a  forced 
blast  from  a  fan  or  blower.  In  either  case  the  air  is  generally 
admitted  to  the  cupola  through  openings  in  the  sides  near  the 
bottom.  These  openings  are  known  as  tuyeres  or  tuyere  holes. 
The  location,  size,  number  and  shape  of  these  tuyeres  are  a  mat- 
ter of  prime  importance  in  constructing  a  cupola,  and  are  a  sub- 
ject to  which  a  great  deal  of  attention  has  been  given  by 
eminent  and  practical  foundrymen  for  years,  and  to  these  men 
is  due  the  credit  for  the  advancement  made  in  the  construction 
of  cupolas. 

It  is  only  a  few  years  since  10  to  15  tons  was  considered  a 
large  heat  for  a  cupola,  and  when  a  large  casting  was  to  be 
poured  two  or  more  cupolas  were  run  at  the  same  time  and  the 
greater  part  of  a  day.  consumed  in  melting.  Now  60  tons  are 
melted  in  one  cupola  in  four  hours  for  light  foundry  work,  and 
hundreds  of  tons  are  melted  in  one  cupola  in  steel  works  with- 
out dropping  the  bottom.  This  improvement  in  melting  is 
largely  due  to  the  improvement  in  the  size,  shape  and  arrange- 
ment of  tuyeres. 

There  have  been  epidemics  of  tuyere  inventing  several  times 
in  this  country  in  the  past  twenty-five  years,  and  during  these 
periods  it  has  been  almost  impossible  for  an  outsider  to  get  a 
look  into  a  cupola  for  fear  the  great  secret  of  melting  would  be 
discovered  in  the  shape  of  the  tuyere  and  made  public.  Dur- 
ing these  epidemics  tuyeres  of  almost  every  conceivable  shape 
have  been  placed  in  cupolas,  and  great  results  in  melting 

(30) 


CUPOLA   TUYERES.  31 

claimed  for  them.  Many  of  these  tuyeres  were  soon  found  to 
be  complicated  and  impracticable,  or  the  advantage  gained  by 
their  use  in  melting  was  more  than  offset  by  extravagant  use 
of  fuel. 

It  would  be  useless  for  us  to  describe  all  the  tuyeres  we  have 
seen  employed,  for  many  of  them  were  never  used  out  of  the 
foundry  in  which  they  were  invented,  and  only  used  there  for  a 
short  time.  We  shall,  therefore,  describe  only  a  few  of  those  that 
have  been  most  extensively  used  or  are  in  use  at  the  present 
time. 

The  round  tuyere  is  probably  the  oldest  or  first  tuyere  ever 
placed  in  a  cupola.  It  was  used  in  cupolas  and  blast  furnaces 
in  Colonial  days  in  this  country,  and  long  before  that  in  France 
and  other  countries.  In  the  old-fashioned  cast  iron  stave 
cupolas  three  round  tuyeres  were  generally  placed  in  a  row, 
one  above  another,  on  opposite  sides  of  the  cupola.  The  first 
or  lower  tuyere  was  placed  from  18  to  24  inches  above  the 
sand  bottom,  and  the  others  directly  over  it  from  3  to  4  inches 
apart.  The  tuyere  nozzle  or  elbow  was  attached  to  the  blast- 
pipe  by  a  flexible  leather  hose,  and  first  placed  in  the  lower 
tuyere  and  the  two  upper  tuyeres  temporarily  closed  with  clay. 
When  a  small  heat  was  melted  the  nozzle  was  permitted  to  re- 
main in  the  lower  tuyere  through  the  heat.  But  when  a  large 
heat  was  melted  and  the  cupola  melted  poorly  at  any  part  of 
the  heat,  or  if  molten  iron  was  to  be  collected  in  the  cupola  for 
a  large  casting,  the  clay  was  removed  from  the  upper  tuyeres, 
and  the  nozzle  removed  from  one  to  the  other,  as  required,  and 
the  lower  tuyeres  closed  with  clay. 

In  these  cupolas  the  tuyeres  were  generally  too  small  to  ad- 
mit a  proper  volume  of  blast  to  do  good  melting.  In  one  of 
28  inches  diameter  we  recently  saw  at  Jamestown,  N.  Y.,  the 
original  tuyeres  were  only  3  inches  in  diameter.  Two  tuyeres 
of  this  size  could  not  possibly  admit  a  sufficient  volume  of  blast 
to  do  good  melting  in  a  cupola  of  the  above  diameter,  and  in 
this  one  they  had  been  replaced  by  two  of  a  much  larger  diam- 
eter placed  at  a  lower  level  than  the  old  ones.  The  round 


32  THE   CUPOLA   FURNACE. 

tuyere  is  still  extensively  used  in  small  cupolas  where  the 
tuyeres  can  be  made  of  a  diameter  not  to  exceed  5  or  6  inches, 
but  in  large  cupolas  it  has  generally  been  replaced  by  the  flat 
or  oval  tuyere,  which  admits  the  same  volume  of  blast  and  per- 
mits of  a  smaller  amount  of  fuel  being  used  in  the  bed  than 
could  be  used  with  a  round  tuyere  of  large  area. 

OVAL   TUYERE. 

In  Fig.  2  is  shown  the  oval  or  oblong  tuyere  now  extensively 
used.  It  is  made  of  different  sizes  to  suit  the  diameter  of 
cupola,  the  most  common  sizes  used  being  2x6,  3x8,  and 
4x12  inches.  They  are  laid  flat  in  the  lining  and  generally 
supplied  from  an  outside  belt  air  chamber.  This  tuyere  is  the 
one  most  commonly  used  by  stove,  bench  and  other  foundries 
requiring  very  hot  iron  for  their  work.  They  are  placed  very 
low,  generally  not  more  than  two  or  three  inches  above  the 
sand  bottom,  and  in  large  cupolas  the  slope  of  the  bottom  fre- 
quently brings  it  up  to  the  bottom  of  the  tuyeres  on  the  back 
side  of  the  cupola.  This  tuyere  admits  the  blast  to  a  cupola 
as  freely  as  a  rounded  tuyere  of  the  same  area,  and  the  tendency 
of  the  stock  to  chill  over  the  tuyeres  in  settling  and  bridge  the 
cupola  is  no  greater  than  with  a  round  tuyere  of  the  same 
capacity.  It  admits  of  a  lower  bed  than  the  round  tuyere, 
and  is  to  be  preferred  to  the  round  form  for  cupolas  requir- 
ing tuyeres  of  larger  area. 

EXPANDED  TUYERE. 

In  Fig.  3  is  seen  the  expanded  tuyere,  which  is  made  larger 


FIG.  3. 


FIG.  2. 


CUPOLA  TUYERES — OVAL  TUYERE.  EXPANDED  TUYERE. 

at  the  outlet  than  at  the  inlet.     It  is  reduced  at  the  inlet  so 


CUPOLA  TUYERES.  33 

that  the  combined  tuyere  area  may  correspond  with  the  outlet 
of  the  blower  and  equalize  the  volume  of  blast  entering  the 
cupola  at  each  tuyere  from  the  air  belt.  It  is  expanded  at  the 
outlet  to  permit  the  blast  to  escape  freely  from  the  tuyeres  into 
the  cupola,  and  in  case  the  stock  settles  in  the  front  of  the 
tuyere  in  such  a  way  as  to  close  up  part  of  it,  there  may  still  be 
sufficient  opening  for  the  full  volume  of  blast  entering  the 
tuyere  to  pass  into  the  cupola.  The  tuyere  is  made  from  two 
to  four  inches  wide  at  the  inlet  and  six  to  twelve  inches  long. 
The  width  of  the  outlet  is  the  same  as  that  of  the  inlet,  and  the 
length  of  the  outlet  is  from  one-fourth  to  one-half  longer  than 
the  inlet.  The  tuyere  is  laid  flat  in  the  lining,  the  same  as  the 
oval  tuyere,  and  the  only  advantage  claimed  for  it  over  that 
tuyere  is  that  it  cannot  be  closed  so  readily  by  the  settling  of 
the  stock  and  the  chilling  of  the  iron  or  cinder  in  front  of  it. 
The  expanded  tuyere  is  preferred  by  many  to  the  oval  tuyere 
on  this  account  and  is  extensively  used  at  the  present  time. 

DOHERTY   TUYERE. 

In  Fig.  4  is  seen  the  Doherty  arrangement  of  tuyeres,  designed 
by  Mr.  Doherty  of  the  late  firm  of  Bement  &  Doherty,  Philadel- 
phia, Pa.,  and  employed  in  the  Doherty  cupola,  a  cupola  that  was 
extensively  used  in  Philadelphia  about  twenty-five  years  ago. 
The  arrangement  consists  of  two  or  more  round  tuyeres  placed 
in  the  lining  and  at  an  angle  to  it,  instead  of  passing  straight 
through  the  lining  as  tuyeres  generally  do.  The  blast  pipes 
connecting  with  each  tuyere  were  placed  at  the  same  angle  as 
the  tuyere,  the  object  being  to  give  the  blast  a  whirling  or 
spiral  motion  in  the  cupola.  The  blast  took  the  desired  course, 
as  could  b£*  plainly  seen  by  its  action  at  the  charging  door,  and 
it  had  the  appearance  of  making  a  more  intense  heat  in  the 
cupola  than  when  delivered  from  the  straight  tuyere.  But  this 
appearance  was  deceptive,  and  after  careful  investigation  it  was 
found  that  no  saving  in  fuel  was  effected  or  faster  or  hotter 
melting  done  on  account  of  this  motion  of  the  blast.  The 
cupolas  and  tuyeres  were,  however,  constructed  of  proper  pro- 
3 


34 


THE   CUPOLA   FURNACE. 


portions,  and  were  a  decided  improvement  on  the  small  tuyere 
cupolas  in  use  at  that  time.  Many  of  them  were  placed  in 
foundries  and  are  still  in  use,  but  no  importance  is  attached  to 
the  spiral  motion  of  the  blast. 

SHEET   BLAST  TUYERE. 

In  Fig.  5   is  seen  the  horizontal  slot  tuyere.     This  tuyere 
FIG.  4. 


FIG.  5. 


SHEET  BLAST  TUYERE. 


DOHERTY  TUYERE. 


consists  of  a  slot  from  one  to  two  inches  wide,  extending  one- 
third  around  the  cupola  on  each  side,  or  a  continuous  slot  ex- 
tending all  the  way  around  the  cupola.  The  slot  is  formed  by 
two  cast  iron  plates,  on  one  of  which  are  cast  separating  bars 
to  prevent  the  plates  being  pressed  together  by  the  weight  of 
the  lining  or  warped  by  the  heat.  This  tuyere  is  known  as  the 
sheet  blast  tuyere.  It  admits  of  a  smaller  amount  of  fuel  being 
used  for  a  bed  than  any  other  tuyere  placed  in  a  cupola  at  the 
same  height  above  the  bottom.  It  distributes  the  blast  equally 
to  the  stock,  and  does  fast  and  economical  melting  in  short 
heats.  But  the  tendency  of  the  cupola  to  bridge  is  greater 
than  with  almost  any  other  tuyere,  and  a  cupola  with  this 
tuyere  cannot  be  run  successfully  for  a  greater  length  of  time 
than  two  hours. 

MACKENZIE   TUYERE. 

In  Fig.  6  is  seen  the  Mackenzie  tuyere,  designed  by  a  Mr. 
Mackenzie  of  Newark,  N.  J.,  and  used  in  the  Mackenzie  cupola. 
This  is  a  continuous  slot  or  sheet  blast  tuyere,  but  differs  from 


CUPOLA  TUYERES. 


35 


the  one  just  described  in  that  the  cupola  is  boshed  and  the 
bosh  overhangs  the  slot  from  four  to  six  inches.  The  slot  is 
protected  by  the  overhanging  bosh  and  cannot  be  closed  up  by 

FIG.  6. 

T 


SHELL  ANGLE  IRONigifll 


MACKENZIE  TUYERE. 


the  settling  of  the  stock.  The  Mackenzie  cupolas  with  this 
tuyere  are  constructed  of  an  oval  or  oblong  shape,  with  an  inside 
belt  air  chamber.  The  blast  enters  the  air  chamber  from  a  tuyere 
box  at  each  end  of  the  cupola,  and  passes  into  the  cupola 
through  a  two-inch  slot  extending  all  the  way  round  the  cupola. 

BLAKENEY  TUYERE. 

In  Fig.  7  is  seen  the  Blakeney  tuyere  used  in  the  Blakeney 
cupola  constructed  by  The  M.  Steel  Company,  Springfield,  Ohio. 


THE    CUPOLA   FURNACE. 


This  tuyere  is  a  modification  or  an  improvement  on  the  sheet 
blast  tuyere,  and  extends  all  the  way  around  the  cupola.     It  is 

FIG.  7. 


BLAKENEY    TUYERE. 

supplied  from  an  outside  belt  air  chamber  riveted  to  the  shell. 
The  blast  is  conducted  to  the  air  chamber  through  one  pipe, 
and,  striking  the  blank  spaces  sidewise  in  rear  of  chamber, 
passes  all  around  through  the  curved  tuyeres  into  the  centre  of 
the  furnace.  This  tuyere  admits  the  blast  freely  and  evenly  to 
the  cupola  and  very  good  melting  is  done  with  it.  All  the 
tuyeres  described  above  may  be  used  with  either  coal  or  coke. 

HORIZONTAL   AND   VERTICAL   SLOT   TUYERE. 

In  Fig.  8  is  seen   the   horizontal   and   vertical   slot  tuyere. 

FIG.  8. 


HORIZONTAL  AND  VERTICAL   SLOT  TUYERE. 

This  was  designed  for  coke,  and  we  have  seen  it  used  in  but 
one  cupola,  a  4O-inch  one.     One  tuyere  was  placed  on  each 


CUPOLA  TUYERES. 


37 


side  of  the  cupola.  The  horizontal  slot  of  each  tuyere,  I  inch 
wide,  extended  one-third  way  round  the  cupola,  and  the 
vertical  slots,  I  inch  wide  and  12  inches  long,  were  placed 
above  it  as  shown.  The  tuyere  did  excellent  melting,  and  the 
cupola  could  be  run  for  a  long  time  without  bridging. 

REVERSED   "f   TUYERE. 

In  Fig.  9  is  seen  a  vertical  and  horizontal  slot  or  reversed  T 
tuyere,  also  used  for  coke.  The  slots  in  this  tuyere  are  from 
two  to  three  inches  wide  and  ten  to  twelve  inches  long.  From 
two  to  eight  of  these  tuyeres  are  placed  in  a  cupola,  according 
to  the  diameter.  This  tuyere  has  been  extensively  used,  and 
is  said  to  be  an  excellent  tuyere  for  coke  melting. 


FIG.  9. 


FIG.  10. 


FIG.  ii. 


REVERSED    TUYERE. 


VERTICAL  SLOT  TUYERE.   VERTICAL  SLOT  TUYERE. 


In  Figs.  10  and  n  are  seen  the  vertical  slot  tuyeres  used 
principally  in  cupolas  of  small  diameter  to  prevent  bridging. 
They  are  made  from  two  to  three  inches  wide  and  ten  to 
twelve  inches  long,  and  two  or  more  are  placed  in  a  cupola  at 
equal  distances  apart. 

TRUESDALE  REDUCING  TUYERE. 

In  Fig.  12  is  seen  the  Truesdale  reducing  tuyere  designed 
by  a  Mr.  Truesdale  of  Cincinnati,  Ohio,  and  extensively  used  in 
cupolas  in  that  vicinity  about  1874.  The  tuyere  consisted  of 
one  opening  or  tuyere  placed  directly  over  another  until  six, 
eight  or  ten  tuyeres  were  put  in.  The  lower  tuyere  was  made 


THE   CUPOLA   FURNACE. 


three  or  four  inches  in  diameter,  and  tuyeres  above  it  were 
placed  one  inch  apart,  and  each  one  made  of  a  smaller  diam- 


FlG.  12. 

o 
o 
O 

O 
O 


FIG.  13. 


FIG.  14. 


O 

O 

o 


TRIANGULAR  TUYERE. 


TRUESDALE  REDUCING 
TUYERE. 


LAWRENCE  REDUCING 
TUYERE. 


eter  until  they  were  reduced  to  one  inch.  The  bottom  row  of 
tuyeres  were  placed  two,  four  and  six  inches  apart,  and  the 
tuyeres  in  each  succeeding  row  were  placed  further  apart,  were 
of  a  smaller  diameter  and  admitted  less  blast  to  the  cupola  to- 
ward the  top  of  the  bed  than  at  the  bottom.  The  cupolas  were 
generally  boshed,  and  the  tuyeres  supplied  from  an  inside  belt 
air  chamber,  formed  of  cast  iron  staves,  to  which  the  tuyeres 
were  attached  by  cleats  or  dovetails  cast  on  the  stays.  Very 
fast  melting  was  done  in  cupolas  with  this  tuyere,  but  the  ten- 
dency to  bridge  in  cupolas  of  small  diameter  is  so  great  that 
it  could  not  be  used.  In  large  cupolas,  however,  it  gave  ex- 
cellent results,  and  is  still  in  use  in  numerous  foundries. 

LAWRANCE  REDUCING  TUYERE. 

In  Fig.  13  is  seen  the  Lawrance  reducing  tuyere  designed  by 
Frank  Lawrance  of  Philadelphia,  Pa.,  and  used  in  the  Lawrance 
cupola,  built  by  him.  This  tuyere  was  designed  for  either  coal 
or  coke  melting,  and  works  equally  well  with  either.  The 


CUPOLA  TUYERES.  39 

opening  at  the  bottom  is  from  3  to  4  inches  square,  and  the 
slot  from  10  to  12  inches  long,  from  I  to  i  y2  inches  wide  at  the 
bottom,  and  tapers  to  a  point  at  the  top.  The  tuyeres  are  placed 
in  the  cupola  from  6  to  12  inches  apart,  and  supplied  from  a  belt 
air  chamber  inside  the  casing.  The  air  chamber  in  this  cupola 
was  first  formed  with  cast  iron  staves,  and  the  tuyeres  held  in 
place  by  cleats  cast  upon  the  staves.  But  the  staves  were 
found  to  break  after  repeated  heating  and  cooling,  and  a  boiler 
iron  casing  is  now  used  for  the  air  chamber.  This  tuyere  and 
cupola  do  excellent  melting,  and  a  great  many  of  them  are 
now  in  use. 

TRIANGULAR   TUYERE. 

In  Fig.  14  is  seen  the  triangular  tuyere,  designed  by  the 
writer  over  25  years  ago  to  prevent  bridging  in  small  cupolas 
and  extensively  used  in  both  small  and  large  cupolas,  with 
either  coal  or  coke.  This  tuyere  may  be  made  with  the  base 
and  sides  of  the  tuyere  of  an  equal  length,  forming  an  equilat- 
eral triangle,  or  the  sides  may  be  made  longer  than  the  base, 
bringing  the  tuyere  up  to  a  sharp  point  at  the  top  to  prevent 
bridging  ;  or  the  sides  may  be  extended  up  to  a  sufficient  height 
to  form  a  reducing  tuyere. 

The  Magee  Furnace  Company,  Boston,  Mass.,  placed  this 
tuyere  in  their  large  cupola,  constructed  to  melt  iron  for  stove 
plate,  about  twelve  years  ago,  and  it  has  been  in  constant  use 
ever  since,  giving  excellent  results  in  melting  with  coal  and 
coke.  In  this  cupola,  which  is  5  feet  4  inches  diameter  at  the 
melting  point,  the  tuyere  is  9  inches  wide  at  the  base  and  16 
inches  high.  It  was  not  thought  best  to  extend  the  tuyere  up 
to  a  point  at  so  sharp  an  angle,  and  the  top  was  cut  off,  leaving 
the  opening  2  inches  wide  at  the  top.  This  tuyere  has  been 
arranged  to  take  the  place  of  the  Truesdale  reducing  tuyere, 
and  has  been  made  from  6  to  8  inches  wide  at  base  and  24  to 
30  inches  high,  running  up  to  a  point.  It  has  also  been  used 
in  imitation  of  the  Lawrance  reducing  tuyere  and  made  from  3 
to  4  inches  wide  at  base  and  12  to  16  inches  high. 


40  THE    CUPOLA   FURNACE. 

WATER  TUYERE. 

In  Fig.  15  is  seen  the  water  tuyere.  This  tuyere  is  designed 
to  be  used  in  cupolas  or  furnaces  where  the  whole  or  part  of 
the  tuyere  is  exposed  to  an  intense  heat  and  liable  to  be  melted 
or  injured,  as  is  the  case  with  tuyeres  placed  in  the  bottom  of  a 
cupola  or  in  furnaces  where  a  hot  blast  is  used. 

The  tuyere  or  metal  surrounding  the  tuyere  opening  is  cast 
hollow  and  filled  with  water,  or  one  end  is  left  open  and  a  spray 
thrown  against  the  end  exposed  to  the  heat  from  a  small  pipe, 
as  shown  in  illustration.  The  tuyere  is  also  made  with  a  coil 

FIG.  i 6. 


FIG.  15. 


WATER  TUYERE. 


COLLIAU  TUYERE. 


of  gas  pipe  cast  inside  the  tuyere  through  which  water  con- 
stantly flows.  The  water  tuyere  is  never  used  in  cupolas  when 
the  tuyeres  are  placed  in  the  sides  of  the  cupola,  but  it  has 
been  used  in  cupolas  in  which  the  tuyere  was  placed  in  the 
bottom  and  exposed  to  the  heat  of  molten  iron,  cinder  and 
slag.  When  used  in  this  way  the  tuyere  is  placed  in  the  centre 
of  the  bottom  and  is  made  from  I  to  3  feet  long,  the  mouth 
being  placed  at  a  sufficient  height  above  the  sand  bottom  to 


CUPOLA   TUYERES.  41 

prevent  molten,  iron  or  slag  overflowing  into  it.  The  part  of 
the  tuyere  extending  up  in  the  cupola  and  exposed  to  the  heat 
is  protected  and  prevented  from  melting  by  the  stream  of  water. 
For  this  purpose  the  coil  gas  pipe  tuyere  is  better  than  the 
hollow  or  spray  tuyere  just  described. 

COLLIAU   TUYERE. 

In  Fig.  1 6  is  seen  the  Colliau  double  tuyere  designed  by  the 
late  Victor  Colliau  of  Detroit,  Mich.,  and  used  in  the  Colliau 
cupola.  In  this  cupola  the  tuyeres  are  placed  in  two  rows  one 
above  the  other  in  place  of  one  row  as  in  the  ordinary  cupola. 
The  first  row  is  placed  at  about  the  same  height  above  the  sand 
bottom  as  in  the  ordinary  cupola  and  the  second  row  from  12 
to  1 8  inches  above  the  first  row.  The  first  row  are  flat,  slightly 
expanded  tuyeres  similar  to  that  shown  in  Fig.  2,  and  are  made 
from  2  to  4  inches  wide  and  6  to  14  inches  long,  according  to 
the  size  of  the  cupola.  The  tuyeres  in  the  second  row  are 
made  round  and  from  2  to  4  inches  diameter.  The  tuyeres  in 
the  first  row  pass  straight  into  the  cupola  through  the  lining, 
and  those  in  the  second  row  are  pointed  downward  at  a  sharp 
angle,  as  shown  in  the  cut.  The  object  of  the  second  row  is  to 
furnish  sufficient  oxygen  to  consume  the  escaping  gases  and 
create  a  more  intense  heat  at  the  melting  point  than  is  obtained 
with  the  single  row  of  tuyeres  from  the  same  amount  of  fuel. 

WHITING   TUYERE. 

The  Whiting  tuyere,  used  in  the  Whiting  cupola,  manufac- 
tured by  the  Whiting  Foundry  Equipment  Company,  Chicago, 
111.,  was  designed  by  Mr.  Whiting,  a  practical  foundryman  of 
Detroit,  Mich.,  as  an  improvement  on  the  Colliau  tuyere.  The 
Whiting  tuyere  is  a  double  tuyere,  but  differs  somewhat  in 
arrangement  from  the  Colliau  tuyere.  The  first  row  are  flat, 
slightly  expanded  tuyeres,  and  the  second  row  are  of  the  same 
shape  and  made  larger  in  proportion  to  the  lower  row  than  the 
Colliau,  and  the  two  rows  are  not  placed  at  so  great  a  distance 
apart.  Both  the  upper  and  lower  rows  pass  straight  into  the 
cupola. 


42  THE   CUPOLA   FURNACE. 

CHENNEY   TUYERES. 

The  Chenney  tuyere,  designed  by  the  late  Mr.  Chenney,  a 
practical  foundryman  of  Pittsburgh,  Pa.,  is  a  double  tuyere 
very  similar  in  arrangement  to  the  Colliau  and  Whiting 
tuyeres,  the  only  difference  being  that  both  the  upper  and 
lower  rows  point  downward  at  a  sharp  angle  to  the  lining. 

THE    DOUBLE   TUYERE. 

The  double  or  two  rows  of  tuyeres  appears  to  have  first  been 
designed  and  put  into  practical  use  about  1854  by  Mr.  Ireland, 
a  practical  English  foundryman  and  cupola  builder.  In  Ire- 
land's cupolas,  many  of  which  were  in  use  in  England  about 
that  time,  the  tuyeres  were  placed  in  two  rows  about  18  inches 
apart.  Those  in  the  upper  row  were  of  only  one-third  the 
diameter  of  those  in  the  lower,  and  twice  the  number  of 
tuyeres  were  placed  in  the  upper  row  as  were  in  the  lower. 
The  slag  hole  was  also  used  by  Ireland  in  his  cupola,  which 
was  run  for  a  great  many  hours  without  dumping  or  raking 
out,  as  was  the  custom  in  those  days.  These  cupola  appear 
to  have  given  very  good  results  in  long  heats,  but  in  short 
heats  they  were  not  so  satisfactory,  and  in  more  recent  patents 
obtained  by  Mr.  Ireland  the  upper  row  of  tuyeres  was 
abandoned.  The  double  tuyere  was  also  used  in  Voisin's 
cupola,  by  another  English  cupola  designer  and  constructor,  and 
in  Woodward's  steam  jet  cupola,  also  an  English  cupola,  many 
years  before  they  were  introduced  into  this  country  by  Mr. 
Colliau  about  18/6. 

It  is  claimed  for  the  double  tuyere  that  the  second  row  con- 
sumes the  gases  which  escape  with  the  single  tuyere,  and, 
therefore,  a  great  saving  in  fuel  is  effected  in  melting.  That  a 
more  intense  heat  is  created  in  the  cupola  at  the  melting  zone 
by  the  double  tuyere  cannot  be  disputed,  for  the  destruction  of 
lining  is  much  greater  at  this  point  than  with  the  single  tuyere ; 
but  on  the  other  hand,  that  any  saving  in  fuel  is  effected  has 
not  been  proven  by  comparative  tests  made  in  melting  with 
the  double  tuyere  cupola  and  the  single  tuyere  cupola,  when 


CUPOLA  TUYERES.  43 

properly  constructed  and  managed.  On  the  contrary  it  has 
been  proven  that  the  single  tuyere  cupola  is  the  most  econom- 
ical in  fuel  and  lining.  That  the  double  tuyere  melts  iron 
faster  than  the  single  in  cupolas  of  the  same  diameter  is 
undisputed,  and  as  between  the  single  and  double  it  is  only 
a  question  whether  the  time  saved  in  melting  more  than 
compensates  for  the  extra  expense  of  lining.  When  a  double 
tuyere  cupola  is  run  to  its  full  capacity,  the  consumption  of  fuel 
per  ton  of  iron  is  about  the  same  as  the  single  tuyere,  but  in 
small  heats  it  is  much  greater.  This  is  due  to  the  large 
amount  of  fuel  required  for  a  bed,  owing  to  the  great  height  of 
the  upper  tuyeres  above  the  sand  bottom ;  for  the  bed  must  be 
made  about  the  same  height  above  the  upper  tuyeres  as  above 
the  lower  in  a  single  tuyere  cupola,  and  no  greater  amount 
of  iron  can  be  charged  on  the  bed  with  the  double  tuyere 
than  with  the  single.  When  constructing  or  ordering  a  double 
tuyere  cupola,  the  smallest  one  that  will  do  the  work  should 
be  selected,  so  that  the  cupola  may  be  run  to  its  fullest  capacity 
each  heat  and  the  best  results  obtained  in  melting. 

,4  THREE    ROWS   OF   TUYERES. 

A  number  of  large  cupolas  have  been  constructed  with  three 
rows  of  tuyeres,  for  the  purpose  of  doing  faster  melting  than 
can  be  done  with  the  single  or  double  tuyere  cupola.  Prob- 
ably one  of  the  best  melting  cupolas  of  this  kind  in  use  at  the 
present  time  is  one  constructed  by  Abendroth  Bros.,  Port 
Chester,  N.  Y.,  to  melt  iron  for  stove  plate,  sinks,  soil  pipe  and 
plumbers'  fittings.  This  cupola  is  60  inches  diameter  at  the 
tuyeres  and  72  inches  at  the  charging  door,  and  is  supplied 
with  blast  from  36  tuyeres,  placed  in  the  cupola  in  three  hori- 
zontal rows  10  inches  apart,  12  tuyeres  being  placed  in  each  row. 
The  tuyeres  in  the  first  row  are  6  inches  square,  those  in  the 
second  row  4  inches  square,  and  those  in  the  third  row  2 
inches  square.  This  cupola  melts  60  tons  of  iron  in  four  hours, 
which  is  probably  the  fastest  melting  done  in  this  country  for 
the  same  number  of  hours  for  light  work  requiring  hot  iron. 


44  THE   CUPOLA   FURNACE. 

In  the  double  or  triple  tuyere  cupola  the  upper  tuyeres  may 
be  placed  directly  over  a  tuyere  in  the  lower  row,  or  they  may 
be  placed  between  the  tuyeres  of  the  lower  row  at  a  higher 
level.  In  Ireland's  cupolas  double  the  number  of  tuyeres  were 
placed  in  the  upper  row  as  were  in  the  lower  row,  so  that  one 
was  placed  directly  over  each  tuyere  in  the  lower  row  and  one 
between.  In  the  modern  double  tuyere  cupola  the  same  num- 
ber of  tuyeres  are  placed  in  each  row,  and  the  upper  tuyeres 
are  generally  placed  between  those  in  the  lower  row.  The 
object  in  placing  these  tuyeres  in  a  cupola,  as  stated  before,  is 
to  supply  the  oxygen  to  burn  the  unconsumed  gases  escaping 
from  the  combustion  of  fuel  at  the  lower  tuyeres.  If  a  proper 
amount  of  blast  is  admitted  at  the  lower  tuyere  the  cupola  is 
filled  with  gases  at  this  point,  and  it  does  not  make  any  differ- 
ence whether  the  upper  tuyeres  are  placed  over  or  between  the 
lower  ones,  so  long  as  the  tuyeres  are  only  to  supply  oxygen 
to  consume  the  gases  with  which  the  cupola  is  filled.  If  this 
theory  of  producing  heat  by  consuming  the  escaping  gases 
from  the  combustion  of  fuel  is  correct,  they  can  be  consumed 
at  any  point  in  the  cupola,  and  the  row  of  tuyeres  for  this  pur- 
pose should  be  placed  above  the  bed,  and  the  gas  burned  in 
the  first  charge  of  iron  to  heat  it  and  prepare  it  for  melting  be- 
fore it  settles  into  the  melting  zone.  To  consume  these  gases 
only  the  tuyeres  should  be  small,  and  the  number  of  tuyeres  in 
the  upper  rows  should  be  two  or  three  times  greater  than  in 
the  lower  row,  so  as  to  supply  oxygen  to  all  parts  of  the  cupola, 
and  not  permit  the  gases  to  escape  unconsumed  between  the 
tuyeres.  If  the  tuyeres  in  the  second  or  third  rows  are  made 
too  large  in  proportion  to  the  lower  row,  the  supply  of  oxygen 
is  too  great  for  the  combustion  of  the  gases,  and  the  effect  is 
to  cool  the  iron.  In  the  modern  double  tuyere  cupola  this 
theory  is  not  carried  out,  for  the  tuyeres  in  the  second  row  are 
made  big,  and  admit  such  a  large  volume  of  oxygen  at  one 
point  that  if  they  were  placed  high  their  effect  would  be  to 
cool  the  iron  rather  than  heat  it.  But  they  are  placed  low  so 
as  to  force  the  blast  into  the  bed  and  give  a  deeper  melting 


CUPOLA  TUYERES. 


45 


zone,  and  their  effect  is  to  cause  a  more  rapid  combustion  of 
fuel  and  do  faster  melting  than  is  done  in  the  single  tuyere 
cupola  of  the  same  diameter. 

GREINER   TUYERE. 

In  Fig.  17  is  seen  the  Greiner  tuyere.  The  novelty  of  this 
device  consists  in  a  judicious  admission  of  blast  into  the  upper 
zones  of  a  cupola,  whereby  the  combustible  gases  are  con- 
sumed within  the  cupola  and  the  heat  utilized  to  pre-heat 
the  descending  charges,  thereby  effecting  a  saving  in  the  fuel 


FIG.  17. 


necessary  to  melt  the  iron  when  it 
reaches  the  melting  zone.  This  de- 
vice consists  of  a  number  of  upright  gas 
pipes  attached  to  the  top  of  the  wind 
box  around  the  cupola,  with  branch 
pipes  of  i  inch  diameter  extending  into 
the  cupola  through  the  lining  and 
about  i  foot  apart,  from  a  short  dis- 
j^nce  above  the  melting  zone  to  near 
the  charging  door.  It  is  claimed  that 
these  small  pipes  admit  a  sufficient 
amount  of  oxygen  to  the  cupola  to 
burn  the  carbonic  oxide  produced  by 
the  carbonic  acid  formed  at  the  tuyeres  GREINER  TUYERE. 

absorbing  carbon  from  the  fuel  in  its  ascent.  A  great  saving 
in  fuel  is  thus  effected  by  consuming  this  gas  and  preparing 
the  iron  for  melting  before  it  reaches  the  melting  zone.  A 
large  number  of  cupolas  with  this  device  are  in  use  in  Europe, 
and  quite  a  number  in  this  country. 

ADJUSTABLE   TUYERES. 

Tuyeres  are  sometimes  placed  in  a  cupola  so  that  they  may 
be  adjusted  to  conform  with  the  size  of  the  heat  to  be  melted 
or  the  way  the  iron  is  to  be  drawn  from  the  cupola,  and  thus 
save  fuel  in  the  bed.  They  are  placed  low  when  the  heat  is 
small  or  the  iron  is  drawn  from  the  cupola  as  fast  as  melted, 


46  THE   CUPOLA   FURNACE. 

and  placed  high  when  the  heat  is  large  or  when  iron  is  to  be 
held  in  the  cupola  for  a  large  piece  of  work.  One  of  the  best 
arranged  cupolas  of  this  kind  we  have  seen  is  the  cupola  of  the 
Pennsylvania  Diamond  Drill  &  Mfg.  Company,  Birdsboro,  Pa. 
The  air  belt  extending  around  the  cupola  is  riveted  to  the  shell 
about  4  feet  from  the  bottom  plate.  From  this  belt  a  cast  iron 
air  box  bolted  to  the  shell  extends  down  nearly  to  the  bottom 
plate  in  front  of  each  tuyere.  The  front  of  this  box  has  a  slid- 
ing door  extending  full  length  of  the  box.  The  cupola  shell 
has  a  slot  in  front  of  each  box  the  full  length  of  the  box.  On 
each  side  of  this  slot  a  piece  of  angle  iron  is  riveted  to  the  shell 
to  hold  the  lining  in  place.  The  slot  is  filled  in  with  fire-brick, 
and  a  tuyere  opening  is  left  at  any  desired  height  from  the 
bottom.  When  it  is  desired  to  lower  the  tuyere  the  brick  are 
removed  from  the  bottom  of  the  tuyere  and  placed  at  the  top, 
and  held  in  place  by  a  little  stiff  daubing  or  clay,  and  when  it 
is  desired  to  raise  it  the  brick  are  removed  from  the  top  and 
placed  at  the  bottom  when  making  up  the  cupola.  With  the 
Colliau  and  Whiting  style  of  air  belt  an  adjustable  tuyere  can 
be  arranged  in  this  way  at  a  very  moderate  cost,  and  foundry- 
men  who  think  they  must  have  their  tuyeres  placed  high  so 
they  can  make  a  large  casting  and  only  make  such  a  casting 
once  or  twice  a  year,  can  save  a  great  deal  of  fuel  from  the  bed 
by  having  their  tuyeres  arranged  in  this  way.  The  old  plan  of 
putting  in  two  or  three  tuyere  holes  one  above  the  other,  and 
adjusting  the  tuyeres  during  the  heat  by  raising  the  tuyere 
pipe  from  one  to  the  other,  is  not  practicable  with  the  modern 
way  of  charging  a  cupola,  and  has  long  since  been  abandoned. 

BOTTOM  TUYERE. 

In  Fig.  1 8  is  seen  the  bottom  or  center  blast  tuyere.  This 
tuyere,  as  will  be  observed,  passes  up  through  the  bottom  of 
the  cupola  instead  of  through  the  sides,  and  admits  the  blast 
to  the  center  of  the  cupola  at  the  same  level  as  the  side 
tuyeres.  It  is  not  designed  to  change  the  nature  of  the  iron 
by  forcing  the  blast  through  the  molten  iron  in  the  bottom  of 


CUPOLA   TUYERES. 


47 


the  cupola,  and,  in  fact,  the  blast  has  no  more  effect  upon  the 
quality  of  iron  when  admitted  in  this  way  than  when  admitted 
through  side  tuyeres.  A  tuyere  when  placed  in  the  bottom  of 
a  cupola,  unlike  a  side  tuyere,  is  brought  in  direct  contact 
with  heated  fuel  and  molten  iron,  and  it  must  be  made  of  a 
refractory  material,  or  protected  by  a  refractory  material  if 


FIG  i 8. 


BOTTOM   TUYERE. 


made  of  metal.  The  tuyere  shown  in  the  cut  is  made  of  cast 
iron  and  is  provided  with  a  water  space  between  the  outside 
and  the  inside,  through  which  a  stream  of  water  constantly  flows, 
when  the  tuyere  is  in  use,  from  a  small  pipe  connected  with  a 
tank  placed  alongside  the  cupola  or  on  the  scaffold.  But  it 
has  not  been  found  necessary  to  keep  the  tuyere  cool  with 
water  in  short  heats,  for  the  heat  in  a  cupola  under  the  tuyeres 
is  not  sufficiently  intense  to  melt  cast  iron,  and  the  tuyere  may 
be  sufficiently  protected  against  molten  iron  dropping  upon  it 
or  coming  in  contact  with  it  by  a  thick  daubing  of  refractory 
material  held  in  place  by  the  prickers  cast  on  the  tuyere. 
The  mouth  of  a  bottom  tuyere  must  be  covered  to  prevent 


48  THE   CUPOLA   FURNACE. 

molten  iron,  slag  and  fuel  dropping  into  it  in  their  descent 
to  the  bottom  of  the  cupola.  This  is  done  with  a  rounded 
cap  placed  on  top  of  the  tuyere  to  throw  off  the  molten  iron 
and  slag,  and  the  blast  is  admitted  to  the  cupola  through  an 
opening  around  the  tuyere  under  the  cap,  as  indicated  by  the 
arrows.  The  tuyere  must  be  carefully  dried  and  daubed  be- 
fore it  is  put  in  place.  It  cannot  be  attached  to  the  bottom 
doors  and  must  be  put  in  place  through  a  hole  in  the  doors 
after  they  are  put  up,  and  withdrawn  in  the  same  way  and 
removed  before  the  cupola  is  dumped,  to  prevent  it  being 
broken  or  injured  in  falling  or  by  the  heat  in  the  dump.  It 
must  have  an  adjustable  and  removable  support,  and  the  sand 
bottom  must  be  made  up  very  carefully  around  it  to  prevent 
leakage  of  molten  iron.  The  tuyere  often  gets  fast  in  the  bot- 
tom and  the  men  are  frequently  burned  in  removing  it,  and 
it  sometimes  gets  filled  with  iron  or  slag,  and  spoils  a  heat. 

The  bottom  tuyere  has  been  tried  a  great  many  times  by 
foundrymen  at  different  periods,  and  is  nothing  new.  In  con- 
versing with  several  told  foundrymen  in  Massachusetts  about 
20  years  ago  we  learned  that  the  bottom  tuyere  had  been  used 
in  that  State  away  back  in  the  4O's,  and  at  one  time  was  quite 
popular  with  foundrymen  there ;  and  we  have  met  a  number  of 
other  old  foundrymen  in  different  sections  of  the  country  who 
had  tried  the  tuyere  years  ago  and  given  it  up.  A  bottom 
tuyere  was  patented  by  B.  H.  Hibler  in  this  country  August 
13,  1867.  Ireland  &  Voisin  used  a  bottom  tuyere  in  their 
cupola  many  years  ago,  and  had  these  practical  men  found 
any  advantages  in  it  over  the  side  tuyere  it  would,  no  doubt, 
have  been  brought  into  general  use  in  cupolas  before  this. 

The  bottom  tuyere  was  brought  prominently  before  the 
foundrymen  of  this  country  by  an  ably  written  article  by 
Thomas  D.  West,  read  before  the  Western  Foundrymen's  As- 
sociation at  Chicago,  111.,  October  18,  1893,  in  which  he 
describes  his  experiments  with  the  tuyere  and  claims  for  it  a 
great  saving  in  fuel  and  cupola  lining.  Since  the  publication 
of  Mr.  West's  article  a  number  of  foundrymen  have  published 


CUPOLA  TUYERES.  49 

their  experience  with  the  tuyere  and  all  claim  it  effects  a  great 
saving  in  lining  and  fuel.  But  if  these  foundrymen  have  not 
discovered  some  new  feature  in  the  tuyere  that  was  overlooked 
by  experimenters  with  it  years  ago,  it  will  never  come  into 
general  use. 

SIZE   OF   TUYERES. 

Foundrymen  make  a  great  mistake  in  placing  small  tuyeres 
in  their  cupolas,  with  a  view  of  putting  the  blast  into  the 
cupola  with  greater  force  and  driving  it  to  the  center  of  the 
cupola  with  the  blower.  Air  may  be  driven  from  a  small 
opening  by  a  blower  with  greater  velocity  than  the  same  vol- 
ume of  air  from  a  large  opening,  but  the  air  from  a  small 
opening  loses  its  velocity  when  it  strikes  a  solid  body,  just  the 
same  as  the  air  from  a  large  opening.  When  the  blast  from  a 
small  tuyere  strikes  the  solid  fuel  in  front  of  it,  its  velocity 
is  gone  and  it  will  not  penetrate  any  further  into  the  stock 
than  the  same  volume  of  blast  from  a  large  tuyere.  It  is  not 
the  velocity  at  which  the  blast  passes  into  a  cupola  that  drives 
it  to  the  center,  but  the  force  behind  the  blast.  Neither  is  it 
the  velocity  of  the  blast  that  does  the  melting.  It  is  the  vol- 
ume of  blast.  It  therefore  follows  that  nothing  is  gained  in 
melting  by  forcing  the  blast  through  a  small  tuyere  into  a 
cupola  with  great  velocity,  and  much  is  lost  by  increasing  the 
power  required  to  run  the  blower  to  force  the  blast  through 
a  small  tuyere. 

The  small  tuyere  was  one  of  the  greatest  mistakes  made  in 
the  old-fashioned  stave  cupola.  In  these  cupolas,  many  of 
which  we  have  seen,  only  two  tuyeres  of  3  or  4  inches  diameter 
were  placed  in  a  3O-inch  cupola,  and  the  improvement  made  in 
melting  in  the  modern  cupola  is  largely  due  to  the  enlarge- 
ment of  the  tuyeres  and  the  free  admission  of  blast  to  the 
cupola. 

The  combined  tuyere  area  of  a  cupola  should  be  equal  to 
three  times  the  area  of  the  outlet  of  the  blower  when  the 
blower  is  of  a  proper  size  for  the  cupola.  These  dimensions 

4 


5O  THE   CUPOLA   FURNACE, 

may  seem  large  at  first  sight,  but  it  must  be  remembered  that 
the  size  or  area  of  a  tuyere  when  a  cupola  is  not  in  blast  does 
not  represent  the  area  of  the  tuyere  when  a  cupola  is  in  blast 
or  the  volume  of  blast  that  may  be  admitted  to  the  cupola  by 
the  tuyere.  When  a  cupola  is  in  blast  the  space  in  front  of 
the  tuyere  is  filled  with  fuel '  weighted  down  by  tons  of  iron. 
This  fuel  closes  the  mouth  of  the  tuyere,  and  the  outlet  is  rep- 
resented by  the  number  of  crevices  between  the  pieces  of  fuel 
through  which  the  blast  may  escape.  Should  a  large  piece  of 
fuel  fall  in  front  of  a  tuyere  the  blast  cannot  remove  it  and  the 
tuyere  may  be  closed  and  rendered  useless.  Small  tuyeres 
are  more  liable  to  be  closed  in  this  way  than  large  ones, 
and  for  this  reason  they  should  never  be  placed  in  a  cupola. 
Small  tuyeres,  furthermore,  are  not  only  more  liable  to  be 
stopped  off  by  the  fuel  but  also  tend  to  promote  bridging  by 
admitting  an  insufficient  amount  of  blast  at  certain  points. 

HEIGHT  OF  TUYERE. 

There  is  a  wide  difference  of  opinion  among  foundrymen  as 
to  the  height  or  distance  tuyeres  should  be  placed  in  a  cupola 
above  the  sand  bottom.  So  great  is  this  difference  of  opinion 
at  the  present  time  that  tuyeres  are  placed  in  cupolas  at  from 
2  inches  to  5  feet  above  the  sand  bottom.  This  wide  variation 
in  the  height  of  tuyeres  is  due  to  some  extent  to  the  different 
classes  of  work  done  in  different  foundries,  it  being  claimed  by 
foundrymen  making  heavy  work  that  it  is  necessary  to  have 
the  tuyeres  high  to  hold  molten  iron  in  the  cupola  and  keep  it 
hot  for  a  large  casting.  Foundrymen  making  light  castings 
requiring  very  hot  iron  draw  the  iron  as  fast  as  melted,  and  do 
not  think  it  necessary  to  have  high  tuyeres  to  hold  iron  in  the 
cupola.  In  the  many  experiments  we  have  made  in  melting 
iron  in  a  cupola,  we  have  placed  the  tuyeres  at  various  distances 
above  the  sand  bottom,  and  closely  observed  the  effect  of 
tuyeres  at  different  heights.  We  learned  by  these  experiments 
that  the  fuel  under  the  tuyeres  is  not  consumed  in  melting, 
nor  is  it  wasted  away  to  any  extent  by  the  heat  or  molten  iron 


CUPOLA  TUYERES.  51 

coming  in  contact  with  it.  Charcoal  may  be  placed  in  the 
bottom  of  a  cupola,  and  if  care  is  taken  to  prevent  it  being 
consumed  by  admission  of  air  through  the  front  before  the 
blast  is  put  on,  the  charcoal  will  not  be  consumed  during  the 
heat  and  may  be  found  in  the  dump.  We  have  tried  this  in  our 
experiments  to  soften  hard  iron  by  bringing  the  molten  metal 
in  contact  with  charcoal  in  the  bottom  of  a  cupola,  and  found 
it  correct.  Pieces  of  charred  wood  used  in  lighting  up  are 
often  found  in  the  dump  after  having  remained  in  the  cupola 
through  a  heat.  If  these  soft  combustible  substances  are  not 
consumed  under  the  tuyeres,  then  it  is  not  at  all  likely  that  the 
less  Combustible  hard  coal  and  coke  are  consumed.  No  iron 
can  be  melted  in  a  cupola  under  the  tuyeres,  and  the  only 
function  of  the  fuel  below  the  tuyeres  is  to  support  the  stock 
in  a  cupola  above  the  tuyeres.  If  there  is  not  sufficient  heat 
in  the  bottom  of  a  cupola  to  consume  wood  or  charcoal,  then 
there  is  not  sufficient  heat  to  keep  molten  iron  hot  for  any 
length  of  time;  and  it  is  a  well-known  fact  among  practical 
foundrymen  that  large  bodies  of  molten  iron  can  be  kept  hot 
and  fluid  for  a  greater  length  of  time  in  a  ladle  when  covered 
with  charcoal  to  exclude  the  air  than  it  can  be  in  a  cupola. 

Another  reason  given  in  favor  of  high  tuyeres  is  that  it  is 
necessary  to  have  them  high  to  tap  slag  in  long  heats.  The 
only  slag  in  a  cupola  that  can  be  drawn  through  a  slag  hole  is 
a  light  fluid  slag  that  floats  on  top  of  the  molten  iron  or  rests 
on  the  bottom  of  the  cupola  when  there  is  no  molten  iron  in 
it,  and  this  slag  may  be  drawn  at  any  point  between  the  sand 
bottom  and  tuyeres.  When  a  slag  hole  is  placed  high,  slag- 
only  can  be  drawn  when  the  cupola  is  permitted  to  fill  up  with 
molten  iron  and  raise  the  slag  upon  its  surface  to  the  slag  hole. 
Slag  may  then  be  drawn  for  a  few  minutes  while  the  cupola  is 
filling  up  with  iron  to  the  slag  hole.  As  soon  as  the  iron 
reaches  the  slag  hole,  however,  it  flows  out  and  must  be  tapped 
from  the  front.  The  slag  then  falls  in  the  cupola  with  the  sur- 
face of  the  iron  as  it  is  drawn  off  and  the  slag  hole  must  be 
closed  to  prevent  the  escape  of  blast  through  it.  Iron  tapped 


52  THE   CUPOLA   FURNACE. 

after  permitting  a  cupola  to  fill  up  to  a  high  slag  hole  is  always 
dull. 

When  a  slag  hole  is  placed  low  it  is  not  necessary  to  have 
the  cupola  fill  up  with  iron  before  slag  can  be  tapped,  for  the 
slag  may  be  drawn  off  the  bottom  of  the  cupola,  and,  further- 
more, the  slag  hole  may  be  opened  and  permitted  to  remain 
open  throughout  a  heat  without  waste  of  blast.  The  flow  of  slag 
regulates  itself  when  the  hole  is  of  proper  size.  It  is,  there- 
fore, not  necessary  to  place  tuyeres  high  that  slag  may  be 
drawn  from  a  cupola,  nor  is  it  necesssary  to  hold  iron  in  a 
cupola  for  a  large  casting  or  to  keep  it  hot.  Molten  iron 
should  be  handled  in  a  ladle  and  not  in  a  cupola. 

Hot  iron  for  light  "work  cannot  be  made  in  cupolas  with  high 
tuyeres,  and  for  this  reason  the  tuyeres  in  stove  foundry  cupo- 
las are  always  placed  low.  In  cupolas  of  large  diameter,  hav- 
ing a  large  bottom  surface  for  molten  iron,  the  tuyeres  are 
placed  so  low  that  those  at  the  back  o'f  the  cupola  are  not 
more  than  I  inch  above  the  sand  bottom,  and  those  in  front 
not  more  than  2  or  2^/2  inches  above  the  sand  bottom. 
Tuyeres  placed  in  this  way  give  ample  space  below  them  to 
hold  molten  iron  for  this  kind  of  work,  for  the  iron  must  be 
very  hot  and  is  drawn  from  the  cupola  as  fast  as  melted,  and 
the  cupola  is  large  enough  to  melt  iron  as  fast  as  it  can  be 
handled,  and  it  is  only  when  the  cupola  is  not  working  free 
that  it  is  stopped  up  to  accummulate  iron.  The  tuyeres  in  any 
cupola  may  be  placed  as  low  as  in  these  large  ones,  if  provision 
is  made  for  handling  the  iron  as  fast  as  melted. 

In  smaller  cupolas  not  capable  of  melting  iron  sufficiently 
fast  to  fill  a  40  pound  hand-ladle,  every  8  or  10  seconds  the 
tuyeres  are  placed  from  2  to  4  inches  above  the  sand  bottom, 
so  that  a  sufficient  quantity  of  iron  may  be  collected  before 
tapping  to  give  each  man  in  the  section  catching  a  hand-ladle 
full,  and  fill  the  ladle  in  about  6  seconds. 

In  cupolas  of  very  small  diameter  the  tuyeres  should  be 
placed  from  6  to  10  inches  above  the  sand  bottom.  These  very 
small  cupolas  melt  so  slow  that  if  the  iron  is  drawn  as  fast  as 


CUPOLA  TUYERES.  53 

melted  the  stream  is  so  small  that  the  iron  is  chilled  in  flowing 
from  the  cupola  to  the  ladle  more  than  it  is  by  holding  it  in  the 
cupola  until  a  body  of  iron  is  collected  sufficient  to  supply  a 
large  stream. 

In  machine  and  jobbing  foundry  cupolas  tuyeres  are  gen- 
erally placed  from  18  to  24  inches  above  the  sand  bottom. 
The  object  in  placing  the  tuyeres  so  high  is  to  hold  iron  in  the 
cupola  for  a  large  casting.  But,  as  before  explained,  this  is  not 
necessary  or  advisable.  Another  reason  for  these  high  tuyeres 
is  that  they  are  necessary  for  tapping  slag.  The  slag  from 
many  cupolas  is  drawn  off  at  the  tap  hole  with  the  iron,  and  a 
number  of  spouts  have  been  invented  for  separating  the  slag 
from  the  iron  and  preventing  it  running  into  the  ladle.  Slag 
may  be  drawn  from  the  back  of  a  cupola  on  a  level  with  the 
sand  bottom  at  that  point,  if  the  iron  is  drawn  as  fast  as  melted, 
or  it  may  be  drawn  i,  2  or  more  inches  above  the  sand  bottom 
at  that  point.  It  is,  therefore,  not  necessary  to  place  tuyeres 
at  so  great  a  height  to  tap  slag. 

The  tuyeres  in  cupolas  for  heavy  work  should  be  placed 
from  6  to  8  inches  above  the  sand  bottom  when  slag  is  not  to 
be  tapped.  This  gives  an  abundance  of  room  in  a  cupola  for 
holding  iron  while  removing  or  placing  a  large  ladle,  and  that 
is  all  that  is  necessary.  The  tuyeres  in  many  of  the  cupolas 
used  in  Bessemer  steel  works  are  placed  5  feet  above  the 
bottom.  They  are  probably  placed  at  so  great  a  height  because 
the  tuyeres  in  the  first  cupola  constructed  for  this  work  were 
placed  at  that  height.  Tuyeres  in  all  cupolas  should  be  placed 
as  low  as  they  can  be  for  the  size  of  the  cupola  and  facilities 
for  handling  the  iron,  for  the  fuel  placed  in  a  cupola  under  the 
tuyeres  is  not  consumed  in  melting  and  is  wasted  by  being 
heated  in  the  cupola  and  crushed  and  burned  in  the  dump. 
The  value  of  fuel  wasted  every  year  in  the  United  States  by 
the  use  of  high  tuyeres  in  cupolas  is  sufficient  to  make  a  man 
rich. 


54  THE   CUPOLA   FURNACE. 

NUMBER    OF   TUYERES. 

A  cupola  may  be  supplied  with  blast  from  one  tuyere  placed 
on  one  side  of  the  cupola,  but  the  objection  to  one  tuyere  ar- 
ranged in  this  way  is  that  the  heat  is  driven  by  the  blast 
against  the  opposite  side  of  the  cupola,  and  the  destruction  of 
lining  at  this  point  is  very  great.  For  this  reason,  at  least  two 
tuyeres  are  always  placed  in  a  cupola,  and  they  are  located  on 
opposite  sides  so  that  the  blast  will  meet  in  the  center  and  be 
diffused  through  the  stock.  When  a  greater  number  of  tuyeres 
than  two  are  placed  in  a  cupola  they  are  located  opposite  each 
other  and  at  equal  distances  apart,  to  admit  an  equal  amount  of 
blast  on  all  sides  and  prevent  an  uneven  destruction  of  lining 
from  the  heat  being  forced  unevenly  against  it  by  the  blast. 
Any  number  of  tuyeres  desired  may  be  placed  in  a  cupola, 
and  as  high  as  100  have  been  used  in  a  4O-inch  cupola,  and  a 
greater  number  in  larger  cupolas.  But  these  large  numbers 
have  given  no  better  results  in  melting  than  two  or  four  tuyeres 
in  the  same  cupolas.  It  is  not  necessary  to  place  a  large  num- 
ber of  small  tuyeres  in  a  cupola  to  distribute  the  blast  evenly 
to  the  bed,  and  it  is  not  advisable  to  put  in  small  tuyeres,  which 
are  easily  closed  by  the  fuel,  cinder  and  iron,  and  are  oftener 
rendered  useless  than  large  ones.  Better  results  are  obtained 
from  large  tuyeres  and  fewer  of  them. 

The  largest  cupola  in  use  may  be  supplied  with  blast  by  two 
tuyeres  if  they  are  big  enough.  The  large  cupola  of  the 
Buffalo  School  Furniture  Company,  Buffalo,  N.  Y.,  is  supplied 
with  blast  by  two  tuyeres  12x18  inches,  placed  on  opposite 
sides.  This  cupola,  which  is  60  inches  in  diameter  inside, 
does  excellent  melting  with  only  these  two  tuyeres,  and  the  de- 
struction of  lining  in  melting  is  very  light.  We  saw  a  large 
cupola  with  two  tuyeres  of  about  the  above  dimensions  in  use 
in  a  stove  foundry  in  St.  Louis,  Mo.,  about  20  years  ago,  and  it 
did  excellent  melting.  The  results  obtained  from  these  two 
cupolas  would  go  to  show  that  there  is  nothing  gained  in  dis- 
tributing the  blast  to  the  bed  evenly  by  a  large  number  of 
small  tuyeres.  When  a  number  of  tuyeres  are  placed  in  one 


CUPOLA  TUYERES.  55 

row,  every  other  tuyere  is  sometimes  placed  about  the  width  of 
the  tuyeres  higher  than  the  tuyeres  on  either  side  of  it.  We 
have,  however,  never  observed  that  anything  was  gained  in 
melting  by  placing  tuyeres  in  this  way.  When  a  double  row 
of  tuyeres  is  used  the  upper  row  should  be  made  very  small  in 
comparison  with  the  lower  row,  for  if  they  are  made  of  the 
same  size  as  the  lower  one,  or  even  half  the  size,  and  the  two 
rows  are  placed  at  any  great  distance  apart,  the  heat  is  so  con- 
centra^ed  upon  the  lining  between  them  that  it  may  be  burned 
out  to  the  casing  in  one  or  two  heats.  Foundrymen  using  the 
double  tuyeres,  who  find  the  destruction  of  lining  very  great, 
may  prevent  it  to  some  extent  by  reducing  the  size  of  the 
upper  tuyeres. 

SHAPE  OF  TUYERES. 

The  shape  of  a  tuyere  has  nothing  to  do  with  the  melting, 
except  as  it  may  tend  to  prevent  bridging  or  increase  the  depth 
of  the  melting  zone  by  supplying  blast  to  the  fuel  at  different 
heights  in  a  cupola.  A  small  horizontal  slot  tuyere  extending 
around  a  cupola,  or  the  greater  part  of  the  way  around  it, 
tends  to  promote  bridging,  and  it  is  generally  conceded  that  a 
cupola  with  a  tuyere  of  this  kind  cannot  be  run  for  a  greater 
length  of  time  than  two  hours  without  bridging  and  clogging 
up.  Vertical  slot  and  reducing  tuyeres  supply  blast  to  the  bed 
at  different  levels  and  increase  the  depth  of  the  melting  zone 
the  same  as  the  double  tuyere.  For  this  purpose  the  Trues- 
dale,  Lawrence  and  triangular  tuyere,  with  elongated  sides,  are 
excellent  when  made  of  a  proper  size  and  placed  a  proper 
distance  apart.  When  it  is  not  desired  to  admit  the  blast 
to  the  bed  at  different  levels,  the  flat  or  oval  tuyeres  are 
generally  considered  the  best  shapes,  for  they  admit  the  blast 
freely,  and  a  less  amount  of  fuel  is  required  for  a  bed  with  these 
shapes  than  with  a  round  or  square  tuyere  of  the  same  area. 

TUYERES   TO    IMPROVE   THE   QUALITY   OF    IRON. 

All  kinds  of  fancy-shaped  tuyeres  have  been  placed  in 
cupolas  to  improve  or  change  the  quality  of  iron  in  melting. 


56  THE   CUPOLA   FURNACE. 

They  have  been  placed  to  point  up,  point  down,  point  across 
each  other  at  certain  angles,  and  to  point  to  the  center  of  the 
cupola.  There  is  nothing  more  absurd  than  to  attempt  to  im- 
prove the  quality  of  iron  in  a  cupola  by  the  shape  or  angle  of 
the  tuyeres.  The  instant  the  blast  leaves  the  mouth  of  a 
tuyere  it  strikes  the  fuel  in  front  of  it.  The  shape  or  angle 
given  to  it  by  the  tuyere  is  then  instantly  changed,  and  it 
passes  through  the  crevices  in  the  fuel  until  its  oxygen  enters 
into  combination  with  the  carbon  of  the  fuel  and  produces 
combustion.  It  then  escapes  at  the  top  of  the  melting  zone, 
where  it  comes  in  contact  with  the  iron  as  carbonic  acid  gas. 
This  is  the  result,  no  matter  what  the  shape  or  angle  of  the 
tuyeres,  if  a  proper  amount  of  blast  is  supplied.  It  may  be 
claimed  that  the  blast  acts  upon  the  iron  as  it  drops  through 
the  fuel  in  the  bed  after  being  melted ;  but  as  before  stated,  the 
shape  or  angle  given  to  the  blast  by  the  tuyeres  is  changed  by 
the  fuel,  and  the  effect  en  the  iron  of  the  blast  from  one  tuyere 
would  be  the  same  as  from  another. 

TUYERE    BOXES. 

The  tuyeres  may  be  and  are  often  formed  in  the  lining  of  a 
cupola  when  laying  the  brick,  but  this  is  a  very  poor  way  of 
making  tuyeres,  for  there  is  nothing  to  support  the  brick  and 
maintain  the  shape  of  the  tuyeres,  and  they  are  often  broken 
or  burned  away  until  there  is  no  regular  shape  to  the  aper- 
ture, and  it  is  difficult  to  put  the  blast  into  the  cupola  at  the 
point  desired  or  to  prevent  iron  or  slag  getting  into  the  tuyere. 
Tuyeres  are  more  generally  formed  with  a  cast  iron  lining  or 
tuyere  box,  having  the  shape  and  size  of  tuyere  desired.  This 
box  may  be  cast  with  a  flange  on  one  end  and  be  bolted  to  the 
casing,  or  it  may  be  cast  without  a  flange  and  placed  in  the 
lining  at  the  desired  point  as  it  is  laid  up.  The  boxes  are  made 
in  both  ways,  but  it  is  better  to  cast  it  with  a  flange  and  bolt  them 
to  the  casing,  making  an  air-tight  joint,  as  it  then  insures  the  blast 
going  directly  into  the  cupola  at  the  point  desired,  Tuyere 
boxes  laid  in  a  lining  answer  the  purpose  very  well  when  the 


CUPOLA   TUYERES.  57 

lining  is  new,  but  when  it  becomes  old  and  shaky,  or  a  section 
is  removed  and  replaced,  the  lining  often  settles  and  the  grout- 
ing or  filling  falls  out,  leaving  crevices  through  which  the  blast 
escapes  between  the  casing  and  lining,  and  from  there  enters 
the  cupola  at  points  where  it  does  no  good. 

The  cold  blast  supplied  to  a  cupola  keeps  the  tuyere  box 
cool,  and  it  is  not  necessary  to  cast  it  hollow  and  fill  it  with 
water  to  prevent  it  being  melted  or  injured  by  the  heat.  The 
only  part  of  the  box  that  is  exposed  and  liable  to  be  injured 
is  the  end  next  the  fire,  and  to  protect  it  the  box  at  this  point 
is  generally  cast  about  y2  inch  shorter  than  the  thickness  of  the 
lining  and  the  end  covered  with  a  little  clay  or  daubing. 


CHAPTER  IV. 

CUPOLA  MANAGEMENT. 

THE  peculiarities  in  the  working  of  every  cupola  must  be 
learned  before  it  can  be  run  successfully,  and  this  can  only 
be  done  by  working  it  in  different  ways.  It  is  a  question 
very  much  disputed  whether  a  cupola  constructed  upon  the 
latest  improved  or  patented  design  is  superior  to  one  of  the  old 
style.  This  question  can  only  be  decided  by  the  intelligent 
working  of  each  cupola,  and  the  advantage  will  always  be  found 
in  favor  of  the  one  that  is  properly  worked,  no  matter  what  its 
construction.  It  is  the  duty  of  every  foundryman  to  give  his 
personal  attention  to  the  working  of  his  cupola  if  he  has  time. 
If  he  is  not  a  practical  founder  or  has  not  the  time  to  devote  to 
this  branch  of  the  business  that  it  requires,  then  he  should 
have  his  foundry  foreman  give  it  his  personal  attention  for  a 
sufficient  length  of  time  each  day  to  see  that  everything  is  right 
in  and  about  the  cupola. 

No  cupola  can  be  run  successfully  by  any  given  rule  or  set 
of  rules,  for  conditions  arise  to  which  the  rules  do  not  apply. 
We  shall  therefore  not  only  give  directions  for  the  proper  work- 
ing of  a  cupola  at  every  point,  but  shall  also  give  the  results  or 
effect  of  bad  working  at  every  point,  so  that  the  founder  when 
he  finds  his  cupola  is  not  operating  well  may  have  some  data 
from  which  to  draw  conclusions  and  be  able  to  overcome  the 
difficulty. 

DRYING   THE   LINING. 

The  cupola  having  been  newly  lined,  nothing  is  to  be  done 
to  the  lining  for  the  first  heat  but  to  dry  it.  A  very  high  or 
prolonged  heat  is  not  required  for  this  when  only  one  thick- 
ness of  brick  is  put  in  and  laid  up  in  thin  grout.  The  lining 

(58) 


CUPOLA   MANAGEMENT.  59 

may  be  dried  by  making  a  wood  fire  after  the  sand  bottom  is 
put  in,  or  by  starting  the  fire  for  the  heat  a  little  sooner  than 
usual.  But  the  fire  must  not  be  started  too  early  or  the  bed 
will  be  burned  too  much  and  the  cupola  filled  with  ashes, 
which  wilfretard  the  melting. 

When  a  backing  or  filling  of  wet  clay  or  sand  several  inches 
thick  is  put  in  between  the  casing  and  lining,  more  time  and 
care  are  required  in  drying.  It  must  then  be  dried  slowly  and 
evenly,  or  the  filling  will  crack,  and  when  jarred  in  chipping 
out  will  crumble  and  work  out  through  cracks  in  the  lining  or 
holes  in  the  casing  and  leave  cavities  behind  the  lining. 
When  a  lining  is  put  in  in  this  way,  the  doors  are  put  up  and 
covered  with  sand  and  "a  good  coal  or  coke  fire  is  made  in  the 
cupola  and  allowed  to  remain  in  over  night.  In  the  morning  the 
bottom  is  dropped  to  remove  the  ashes  and  cool  off  the  lining 
before  making  up  the  sand  bottom  for  a  heat. 

PUTTING   UP   THE   DOORS. 

The  first  thing  to  be  done  when  making  up  the  cupola  for  a 
heat  is  to  put  up  the  bottom  doors.  When  the  cupola  is  of 
small  diameter  and  the  door  light  it  may  be  raised  into  place 
and  supported  by  one  man.  But  when  the  door  is  heavy  two 
men  are  required,  and  if  the  cupola  is  a  large  one  and  the  door 
made  in  two  parts,  three  men  are  required  to  lift  and  support 
them.  Two  men  get  inside  the  cupola  and  raise  one-half  into 
place  while  the  third  man  supports  it  with  a  temporary  prop ; 
they  then  raise  the  other  half  as  far  as  it  can  be  raised  with 
their  bodies  between  the  two  doors,  where  it  is  supported  by  a 
temporary  prop.  The  men  then  get  under  the  door  on  their 
hands  and  knees  and  raise  it  into  place  on  their  backs,  and  it  is 
then  supported  by  a  prop. 

Numerous  devices  have  been  arranged  for  raising  the  doors 
into  place,  but  they  soon  get  out  of  order  from  the  heat  of  the 
dump  or  carelessness  in  manipulation,  and  they  have  almost  all 
been  abandoned.  When  the  cupola  is  very  small  and  the  door 
light,  it  is  sometimes  supported  by  an  iron  bolt  attached  to  the 


6O  THE   CUPOLA   FURNACE. 

under  side  of  the  bottom  plate  at  the  front,  where  it  can  be 
readily  withdrawn  with  an  iron  hook  to  drop  the  bottom.  But 
the  doors  are  generally  supported  by  a  stout  iron  prop  or  post 
placed  under  the  door  near  the  edge  opposite  the  hinges. 
Double  doors  are  supported  by  a  stout  iron  prop  in  the  center 
and  generally  a  light  one  at  each  end  of  the  doors  to  prevent 
them  springing  when  charging  the  fuel  and  iron,  or  by  a  sud- 
den settling  of  the  stock,  as  may  occur  when  melting  large 
chunks.  A  great  many  melters  have  no  permanent  foundation 
under  the  cupola  upon  which  to  place  the  main  prop,  but  make 
one  every  heat  by  laying  down  a  small  plate  upon  the  sand  and 
setting  the  prop  upon  it.  The  plate  is  often  placed  too  high 
or  too  low,  making  the  prop  too  long  or  too  short,  and  the 
plate  must  be  raised  by  putting  a  little  more  sand  under  it  or 
lowered  by  scraping  away  a  little  sand.  While  this  is  being 
done  the  heavy  iron  prop,  which  frequently  requires  two  men 
to  handle  in  the  cramped  position  in  which  they  are  placed 
under  the  cupola,  has  often  to  be  put  up  and  taken  down  two 
or  three  times  before  it  is  gotten  into  the  right  position  to 
support  the  doors. 

All  this  extra  labor  can  be  avoided  and  time  saved  by  im- 
bedding a  heavy  cast  iron  block  in  the  floor  or  foundation 
under  the  cupola  for  the  prop  to  rest  upon.  It  must  extend 
down  a  sufficient  distance  to  insure  its  not  being  disturbed 
when  shoveling  out  the  dump.  A  block  6  inches  square  and 
10  inches  long,  placed  with  the  end  level  with  the  floor,  will 
seldom  be  displaced,  and  makes  a  sure  foundation  for  the  prop. 
The  size  of  prop  required  to  support  a  bottom  depends  upon 
the  size  of  cupola.  In  small  cupolas  the  stock  is  supported  to 
a  large  extent  by  pressure  against  the  lining,  while  in  large 
cupolas  the  stock  is  supported  almost  entirely  by  the  prop. 
For  small  cupolas  the  props  are  made  from  I  ^  to  2  inches 
diameter,  and  for  large  cupolas  from  3  to  3^  inches  diameter. 

The  props  for  large  cupolas  not  only  have  a  greater  weight 
to  support,  but  they  are  seldom  pulled  out  of  the  dump  and 
are  therefore,  if  light,  liable  to  be  bent  and  twisted  to  such  an 


CUPOLA   MANAGEMENT.  6 1 

extent  as  to  render  them  useless.  For  this  reason  they  are 
often  made  heavier  than  is  actually  necessary  for  the  support 
of  the  bottom.  Quite  a  number  of  foundrymen  have  adopted 
the  plan  of  attaching  a  ring  to  the  prop  near  the  top  or  bottom 
with  which  to  draw  it  from  the  dump  and  avoid  heating  it.  The 
ring  is  made  large  and  hangs  loosely,  or  as  a  long  loop  which 
stands  out  from  the  prop.  When  the  prop  is  to  be  removed  a 
hook  is  placed  in  the  ring  or  loop  and  a  quick  jerk  given, 
which  releases  it,  and  it  is  at  once  drawn  from  under  the 
cupola. 

Some  of  the  older  melters  never  use  the  iron  prop,  but 
measure  and  cut  a  new  wood  prop  for  their  cupola  every  heat. 
Many  of  them  are  so  superstitious  that  they  think  the  cupola 
would  not  melt  without  the  new  prop,  and  they  would  rather 
give  up  their  job  than  try  it.  Such  melters  are  not  so  plentiful 
now  as  they  were  20  years  ago,  when  we  first  began  traveling  as 
a  melter  through  this  country  and  Canada,  but  we  find  when 
visiting  foundries  there  are  still  a  few  of  them  left. 

DROPPING  THE   DOORS. 

When  it  is  desired  to  drop  the  doors  it  is  done  by  removing 
the  props  or  drawing  the  bolt.  The  small  props  are  first  taken 
out,  being  released  by  a  stroke  of  the  hammer,  and  are  care- 
fully laid  away  so  that  they  will  not  be  bent  by  the  heat  of  the 
dump.  A  long  bar  with  a  handle  on  one  end  and  a  large  hook 
on  the  other  is  then  placed  under  the  cupola  with  the  hook  be- 
hind the  main  prop  and  about  10  or  12  inches  from  it.  By  a 
sudden  jerk  of  the  bar  the  hook  is  made  to  strike  the  bottom 
of  the  prop  a  sufficiently  hard  blow  to  knock  it  out  of  place 
and  permit  the  door  or  doors  to  drop.  Two  or  more  blows  of 
the  bar  are  sometimes  necessary  to  release  the  prop,  but  it  can 
always  be  released  in  this  way.  The  prop  can  also  be  released 
by  striking  it  at  the  top  with  a  straight  bar,  but  it  is  oftener 
missed  than  hit,  and  many  thrusts  are  sometimes  required  to 
bring  it  down.  Bolts  are  only  used  on  small  cupolas  from 
which  the  dump  falls  slowly,  and  the  bolt  can  generally  be  with- 


62  THE   CUPOLA   FURNACE. 

drawn  by  a  blow  of  the  hammer  without  danger  to  the  melter. 
If  it  cannot  be  withdrawn  in  this  way  without  danger  of  burn- 
ing the  melter,  a  hook  is  made  on  the  end  of  the  bolt  or  a  ring 
placed  in  it  so  that  it  may  be  drawn  with  a  hooked  bar  or 
struck  with  a  long  straight  bar.  * 

SAND    BOTTOM. 

When  the  door  or  doors  are  in  place  and  properly  sup- 
ported, any  openings  or  holes  that  may  have  been  burned 
through  them  are  carefully  covered  with  a  thin  plate  of  iron, 
and  all  cracks  through  which  the  bottom  sand  might  escape 
when  dry  are  closed  with  clay.  The  doors  are  then  covered 
with  a  bed  of  sand  several  inches  in  thickness,  which  is  known 
as  the  sand  bottom.  The  sand  employed  for  this  purpose 
must  not  be  of  a  quality  that  will  burn  away  and  permit  the 
molten  iron  to  get  down  to  the  doors,  or  melt  and  form  a  hard 
mass  that  will  not  fall  from  the  cupola  when  the  doors  are 
dropped,  neither  must  it  be  so  friable  as  to  permit  the  molten 
iron  to  run  through  it  when  dry. 

The  clay  sands  when  used  for  a  bottom  burn  into  a  hard, 
tough  mass  that  adheres  to  the  lining  all  around  the  cupola, 
and  in  a  small  cupola  frequently  remains  inplace  after  the  door 
is  dropped  and  has  to  be  dug  out  with  a  bar  before  the  cupola 
can  be  dumped.  Parting  sand,  sharp  and  fire  sands  are  very 
friable  and  difficult  to  keep  in  place.  They  do  not  resist  the 
action  of  the  molten  iron  well,  but  melt  and  form  a  slag. 
Mixtures  of  clay  and  sharp  sand  burn  too  hard  and  do  not  drop 
well.  The  loam  sands  are  the  only  ones  suitable  for  a  sand 
bottom,  and  sand  that  has  been  burned  to  a  limited  extent 
makes  a  better  bottom  than  new  sand. 

In  stove  and  other  foundries  with  large  gangway  floors  the 
scrapings  from  the  gangways  are  collected  in  front  of  the 
cupola,  passed  through  a  No.  2  riddle  to  recover  the  scrap 
iron,  and  the  sand  used  for  the  cupola  bottom.  This  sand 
makes  the  very  best  kind  of  bottom.  It  is  clean  and  free  from 
cinder,  soft  and  pliable,  packs  close,  resists  the  action  of  the 


CUPOLA   MANAGEMENT.  63 

molten  iron  and  drops  free.  In  foundries  where  the  daily 
gangway  cleanings  are  not  sufficient  to  make  the  bottom,  part 
of  the  old  bottom  is  used  over  and  the  gangway  cleanings  are 
mixed  with  it  or  placed  on  top.  In  foundries  where  there  are 
no  regular  gangways  to  clean  every  day,  the  heavy  part  of  the 
dump  is  thrown  out  and  the  sand  bottom  passed  through  a  No. 
2  riddle  and  used  over  again.  When  the  bottom  sand  is  used 
over  day  after  day  it  must  not  be  -riddled  out  too  close,  and  a 
little  fresh  material  must  be  added  to  it  each  day  to  prevent  it 
becoming  rotten  from  repeated  burnings  and  containing  too 
many  small  particles  of  cinder,  which  render  it  fusible  and 
easily  cut  away  by  the  molten  iron.  The  cleanings  from  the 
molding  floors  are  generally  added  or  a  few  shovels  from  the 
sand  heaps,  and  in  case  it  becomes  too  rotten  a  few  shovels  of 
new  molding  sand  are  mixed  with  it. 

When  the  material  contains  so  much  cinder  that  it  does  not 
make  a  smooth  bottom,  a  few  shovels  of  burned  sand  from  the 
heaps  are  put  on  top  to  give  an  even  surface  and  prevent  the 
molten  iron  coming  in  contact  with  the  cinder  and  cutting 
the  bottom.  The  bottom  sand  is  generally  wet  with  water,  but 
some  melters  wet  it  with  clay  wash,  to  make  it  more  adhesive 
and  give  it  more  strength  to  resist  the  action  of  the  molten 
iron.  A  thick  clay  wash  gives  strength  to  a  rotten  sand  when 
mixed  with  it,  but  it  also  increases  the  tendency  of  the  bottom 
to  cake  and  hang  up,  and  it  is  better  to  improve  the  bottom 
material  in  the  way  above  described  and  wet  it  with  water 
only.  The  sand  when  wet  is  cut  over  and  evenly  tempered, 
and  should  be  no  wetter  than  molding  sand  when  tempered  for 
a  mold. 

The  sand  may  be  thrown  into  the  cupola  through  the  front 
opening,  or  may  be  thrown  in  at  the  charging  door,  but  it  is 
generally  thrown  in  at  the  front,  for  it  is  more  convenient  to 
the  material,  and  is  also  convenient  for  spreading  it  in  the 
cupola.  When  the  cupola  is  small  the  melter  stands  by  the 
side  of  it  and  makes  up  the  bottom  by  passing  his  arm  in 
through  the  front  opening,  but  when  the  cupola  is  large  he 


64  THE   CUPOLA   FURNACE. 

goes  inside,  and  his  helper  shovels  the  sand  in  as  he  wants  it. 
The  first  sand  thrown  in  is  carefully  packed  around  the  edges 
with  the  hands  to  insure  a  tight  joint.  «As  the  balance  of  the 
sand  is  thrown  in  it  is  spread  evenly  over  the  bottom  in  layers 
from  i  to  2  inches  thick,  and  each  layer  is  evenly  rammed  or 
trampled  down  until  the  required  thickness  of  bottom  is 
obtained,  which  is  from  3  to  6  inches,  according  to  the  rise  of 
the  cupola.  The  desired  pitch  or  slope  for  throwing  the  iron 
to  the  front  is  then  given,  and  the  bottom  butted  evenly  and 
smoothly  all  over.  The  melter  next  goes  carefully  around  the 
edges  with  his  hands  and  feels  for  any  Soft  spots  there  may  be 
near  the  lining,  and  slightly  raises  the  edges  of  the  bottom 
around  the  lining  to  throw  the  iron  off  and  prevent  it  working 
its  way  down  between  the  lining  and  sand  bottom.  The 
bottom  is  then  carefully  brushed  and  smoothed  off,  and  in 
small  cupolas  a  bucket  of  thin  clay  wash  is  sometimes  thrown 
in  at  the  front  and  caught  in  the  bucket  as  it  runs  out.  This  is 
called  slushing  the  bottom,  and  is  done  to  give  a  smooth,  hard 
surface. 

The  sand  bottom  does  not  always  remain  impervious  to  the 
molten  metal,  but  is  sometimes  penetrated  or  cut  up  and  de- 
stroyed by  it,  in  which  case  a  leakage  of  molten  iron  takes 
place  from  the  bottom  of  the  cupola  that  is  difficult  to  stop. 
Leakage  of  this  kind  may  be  due  to  springing  of  the  bottom 
doors  when  charging  and  the  cracking  or  loosening  of  the  sand 
bottom  around  the  lining.  This  can  be  prevented  by  placing 
more  props  under  the  doors  to  support  them.  Sand  that  has 
been  used  over  and  over  in  a  bottom  until  it  has  become  worn 
out  and  filled  with  cinder  is  readily  cut  up  and  converted  into 
a  slag  by  the  molten  iron,  and  it  is  only  a  question  of  the  time 
occupied  in  running  off  the  heat  whether  the  bottom  gives 
way  or  stands.  When  the  bottom  sand  gets  into  this  condi- 
tion, it  must  be  renewed  by  the  addition  of  new  sand,  or  the 
bottom  covered  with  a  layer  of  sand  from  the  molders'  sand 
heaps. 

Molten  iron  will  not  lie  upon  a  wet,  hard  substance,  but  will 


CUPOLA   MANAGEMENT.  65 

explode  or  boil  and  cut  up  the  material  upon  which  it  is 
placed.  If  the  bottom  sand  is  made  too  wet,  or  rammed  too 
hard,  or  rammed  unevenly,  the  iron  will  not  lie  upon  it,  but 
will  boil  and  cut  up  the  sand  until  it  gets  down  to  the  doors, 
which  it  will  melt  and  run  through.  When  a  bottom  cuts 
through,  melters  frequently  attribute  it  to  the  bottom  being  too 
soft ;  and  we  have  seen  them  take  a  heavy  pounder  and  ram  a 
bottom  as  hard  as  a  stone.  In  these  cases,  if  the  sand  was 
worked  very  dry,  or  the  bottom  was  well  dried  out  before  any 
molten  iron  came  in  contact  with  it,  it  did  not  cut  up  or  leak; 
but  if  the  sand  was  wet  when  the  molten  iron  came  down,  boil- 
ing at  once  took  place  and  the  bottom  soon  cut  through — and 
in  such  cases  they  generally  cut  through  about  every  other 
day.  In  the  sand  bottom  of  a  cupola  we  have  the  same 
elements  to  contend  with,  so  far  as  molten  iron  is  concerned,  as 
we  have  in  a  mold  ;  and  the  sand  should  be  worked  no  wetter, 
rammed  no  harder,  and  rammed  as  evenly  as  the  sand  for  a 
mold.  The  sand  should  not  be  worked  wet  for  a  bottom,  under 
the  impression  that  it  is  dried  out  before  the  iron  comes  down, 
for  the  ashes  of  the  shavings,  wood,  coal  or  coke  cover  the 
bottom  soon  after  the  fire  is  started,  and  protect  it  from  the 
heat  to  such  an  extent  that  it  is  only  dried  to  a  very  limited 
degree  before  the  iron  comes  down  upon  it.  Water  may  be 
seen  dripping  from  a  very  wet  bottom  long  after  the  blast  is 
on.  Even  if  it  were  dried  out,  wet  sand  cracks  when  dried 
rapidly  and  should  not  be  used.  We  shall  not  attempt  to  give 
any  directions  for  stopping  a  leak  after  it  occurs,  for  the  time 
and  place  to  stop  a  leak  is  when  putting  in  the  sand  bottom ; 
and  if  all  the  remedies  we  have  given  for  preventing  leaks  fail, 
then  it  is  time  to  change  the  melter. 

The  pitch  or  slope  given  to  the  bottom  to  cause  the  molten 
iron  to  flow  to  the  tap  hole  from  all  parts  of  the  bottom  has  a 
great  deal  to  do  with  the  temperature  of  the  iron  and  nice 
working  of  a  cupola.  When  the  bottom  is  made  too  low  and 
flat,  molten  iron  lies  in  the  bottom  of  the  cupola  and  becomes 
dull.  As  the  melted  iron  falls  into  this  iron  drop  by  drop,  it  is 
5 


66  THE   CUPOLA   FURNACE. 

instantly  chilled  and  the  iron  when  drawn  from  the  cupola 
is  dull.  This  effect  is  more  marked  in  a  cupola  melting  very 
slowly,  and  a  low  bottom  may  be  the  cause  of  very  dull  iron 
when  a  sufficient  quantity  o^  fuel  is  consumed  to  make  very 
hot  iron.  A  high  pitch  throws  the  iron  from  the  tap  hole  with 
great  force  and  spouting  velocity,  and  it  is  almost  impossible  to 
run  a  continuous  stream  from  a  cupola  with  such  a  bottom. 
It  is  more  difficult  to  keep  the  tap  hole  and  spout  in  order,  and 
the  stream  must  be  closely  watched  to  prevent  it  shooting  over 
the  ladle  and  burning  the  men.  Slag  flows  freely  from  the  tap 
hole  with  the  stream  of  iron  when  the  bottom  has  a  high  pitch, 
even  when  there  is  very  little  slag  in  the  cupola.  But  the  flow 
of  slag  from  the  tap  hole  with  the  iron  may  be  entirely  stopped 
by  changing  the  pitch  of  the  bottom,  no  matter  how  great  the 
quantity  of  slag  in  the  cupola.  The  action  of  the  iron  at  the 
spout  is  entirely  changed  by  the  pitch  of  the  bottom.  A  hard 
iron  may  be  made  to  run  smooth  from  the  spout,  while  a  soft 
iron  may  be  made  to  sparkle  and  fly,  giving  all  the  indications 
of  a  hard  iron.  The  best  expert  on  the  quality  of  iron  at  the 
spout  may  be  deceived  in  the  iron  by  the  pitch  of  the  bottom, 
and  it  is  only  in  the  extremely  hard  and  extremely  soft  iron 
they  cannot  be  deceived.  The  bottom  should  never  be  made 
hollow  in  the  center  and  high  all  around  the  outside  with  -an 
outlet  or  trough  to  the  spout.  This  concentrates  the  iron  in 
the  center  in  such  a  way  that  a  few  hundred  weight  places  as 
great  a  pressure  upon  the  front  as  a  ton  would  do  if  the 
bottom  were  flat,  and  the  front  may  therefore  be  forced  out  by 
a  comparatively  small  body  of  iron.  The  instant  the  tap  hole 
is  open  the  iron  rushes  out  with  great  force,  and  it  is  almost 
impossible  to  stop  it  as  long  as  there  is  any  molten  iron  in  the 
cupola. 

The  bottom  should  be  made  flat  and  level  from  side  to  side 
with  only  a  slight  rise  around  the  lining,  which  should  not  ex- 
tend out  more  than  I  or  2  inches  from  the  lining.  The  pitch 
from  back  to  front  should  not  be  more  than  j£  to  ^  inch  to 
the  foot.  This  has  been  found  to  be  a  sufficient  slope  to  throw 


CUPOLA   MANAGEMENT.  6/ 

all  the  iron  to  the  front  in  an  ordinary  cupola.  But  in  cupolas 
that  melt  very  slowly  a  little  more  slope  may  be  given,  so  as  to 
concentrate  the  iron  more  rapidly  and  prevent  it  chilling  on 
the  bottom. 

In  cupolas  with  two  tap  holes  the  bottom  must  be  sloped  so 
that  all  the  melted  iron  in  the  cupola  can  be  drawn  from  either 
tap  hole.  It  is  very  difficult  for  a  melter  to  see  what  slope  he 
is  giving  a  bottom  when  inside  the  cupola,  and  for  this  reason 
many  of  them  seldom  get  the  slope  alike.  The  melter  should 
be  provided  with  a  notched  stick  or  some  other  gauge,  for 
measuring  down  from  the  top  or  bottom  of  each  tuyere,  to 
serve  as  a  guide  in  sloping  the  bottom,  so  that  it  may  be  given 
the  proper  pitch  and  put  in  alike  every  heat. 

SPOUT. 

The  old  way  of  making  a  cupola  spout  is  to  place  a  short 
piece  of  pig  iron  on  the  bottom  plate  on  each  side  of  the  front, 
and  build  up  a  spout  between  them  with  clay  or  loam.  The 
modern  spouts  are  made  of  cast  iron  with  a  flat  or  eight-square 
bottom,  and  are  from  4  to  6  inches  deep,  7  to  10  inches  wide 
and  i  to  10  feet  long.  They  are  given  a  fall  from  the  cupola 
of  about  I  inch  to  the  lineal  foot,  and  are  lined  with  a  refractory 
material  to  protect  them  from  the  molten  iron.  The  spout 
lining  is  made  of  a  different  material  from  the  sand  bottom,  and 
generally  consists  of  molding  sand,  loam  or  a  mixture  of  fire 
clay  and  sharp  sand.  Some  of  the  molding  sands  make  an 
excellent  spout  lining  that  is  not  cut  or  fused  by  the  stream  of 
molten  iron,  while  others  crumble  and  break  up  too  readily 
when  cleaning  the  spout  of  dross  and  dirt,  and  cannot  be  used 
for  this  purpose.  When  a  molding  sand  can  be  used  it  makes 
a  nice  clean  spout  that  is  easily  and  quickly  made  up.  It  is 
readily  dried,  and  when  making  up  the  spout  the  crust  of  the 
old  lining  can  be  removed  with  a  bar,  and  the  sand  wet  up  and 
used  over  with  a  coating  of  sand  without  removing  it  from  the 
spout.  For  long  spouts,  requiring  a  good  deal  of  material  to 
line  them,  molding  sand  is  the  most  economical  lining  that  can 
be  used. 


68  THE   CUPOLA   FURNACE. 

Some  of  the  loam  and  blue  clays  make  excellent  spout 
linings  alone  or  when  mixed  with  sand,  and  are  the  only 
materials  used  for  this  purpose  in  some  sections  of  the  country 
where  they  can  be  procured  at  a  moderate  cost.  They  make 
a  stronger  lining  than  molding  sand — that  is,  not  so  liable  to  be 
broken  up  when  cleaning  the  spout  of  dross  and  slag — and, 
furthermore,  they  dry  quickly.  The  lining  material  probably 
more  extensively  used  than  any  other  is  a  mixture  of  fire  clay 
and  sharp  sand.  These  two  refractory  substances  when  com- 
bined in  right  proportions  and  thoroughly  mixed  make  one  of 
the  very  best  spout  linings.  But  when  not  properly  mixed 
they  make  one  of  the  poorest  linings. 

When  too  much  clay  is  used  the  lining  does  not  give  up  the 
water  of  combination  until  heated  to  a  very  high  heat,  and  it  is 
almost  impossible  to  get  the  lining  dry  so  that  the  iron  will  not 
boil  in  the  spout  the  first  few  taps  when  the  spout  is  long,  or 
sputter  and  fly  when  it  is  short.  It  cracks  when  dried  rapidly, 
and  is  melted  into  a  tough  slag  that  bungs  up  the  spout  and 
cannot  be  removed  without  destroying  the  lining.  When  too 
much  sand  is  used  the  lining  crumbles  when  touched  with  the 
bar  and  is  cut  and  melted  by  the  stream.  When  the  clay  and 
sand  are  not  thoroughly  mixed  the  lining  crumbles  and  cuts  or 
melts  in  spots.  A  spout  lining  made  of  these  two  materials 
in  right  proportions,  properly  mixed  and  dried,  becomes  as 
refractory  as  a  fire-brick,  and  50  or  100  tons  of  iron  may  be 
run  from  a  spout  lined  with  them  without  a  break  in  the  lining. 
There  are  a  number  of  other  materials  used  for  spout  linings 
that  are  only  found  in  certain  localities,  and  their  use  is  re- 
stricted to  the  districts  where  they  can  be  procured  at  a 
moderate  cost.  But  those  above  described  are  the  materials 
most  commonly  used  for  this  purpose. 

The  spout  lining  is  made  up  new  every  heat,  and  when 
putting  it  in  the  spout  is  wet  to  make  it  adhere  to  it.  The 
sand  bottom  is  cut  away  from  the  front  and  the  spout  lining 
made  to  extend  into  the  cupola  past  the  tap  hole.  A  perfect 
joint  is  made  between  the  sand  bottom  and  spout  lining,  and  a 


CUPOLA   MANAGEMENT.  69 

little  clay  wash  is  generally  brushed  over  the  joint  to  make  it 
more  perfect  and  prevent  cutting.  Care  must  be  taken  to  not 
get  the  bottom  of  the  spout  at  the  tap  hole  higher  than  the 
sand  bottom,  and  also  to  give  it  the  same  pitch  as  the  sand 
bottom.  The  bottom  is  put  in  first  and  is  made  about  T  inch 
thick  when  the  spout  has  been  given  the  proper  pitch.  If  the 
spout  has  not  been  given  a  proper  pitch,  the  lining  is  made 
heavier  at  the  end  next  the  cupola  and  light  at  the  outer  end 
and  the  pitch  given  in  the  lining.  This  is  the  common  practice 
in  short  spouts. 

The  sides  of  the  lining  are  built  up  full  at  the  bottom,  so  as 
to  leave  only  a  narrow  groove  in  the  middle  and  keep  the 
stream  always  in  one  place,  but  are  sloped  back  from  the 
middle  to  the  top  of  the  spout  to  give  a  broad  spout  surface 
for  carrying  the  stream  of  iron.  A  half  round  groove  I  inch 
deep  and  2  inches  wide  at  the  top  is  sufficient  to  carry  off  the 
stream  of  iron  from  almost  any  cupola.  But  the  spout  is  liable 
to  be  choked  up  by  dirt  from  the  tap  hole  or  slag,  and  it  is 
made  large  for  safety.  A  rammer  is  seldom  used  in  making  up 
a  spout,  and  it  is  generally  made  up  with  the  hands  and  one  of 
the  bod  sticks,  or  the  small  round  stick  used  to  make  the  tap 
hole. 

When  molding  sand  is  used  it  is  worked  a  little  wetter  than 
for  moldirig  and  is  beaten  down  with  the  bod  stick  and  shaped 
up  with  the  hands  and  bod  stick.  When  clay  or  a  mixture  of 
clay  and  sand  is  used,  it  is  worked  wet  and  placed  in  the  spout 
in  balls  and  beaten  or  pressed  into  shape  with  the  hands,  and 
the  bod  stick  is  used  to  true  it  up  and  form  the  groove  in  the 
middle.  Short  spouts  are  made  up  with  but  little  difficulty, 
but  great  care  must  be  taken  in  making  up  a  long  spout  to 
have  it  perfectly  true  and  properly  pitched,  so  that  it  will  clean 
itself  of  molten  iron  the  moment  the  cupola  is  stopped  in. 

The  greatest  strain  upon  the  spout  lining  is  under  and 
around  the  tap  hole,  where  it  is  liable  to  be  cut  away  by  the 
pressure  and  current  of  the  stream  or  to  be  melted  if  the 
material  is  not  very  refractory,  and  it  may  be  broken  up  by 


70  THE   CUPOLA   FURNACE. 

the  tap  bar  if  not  very  tenacious  when  heated  to  a  high  tem- 
perature. When  molding  sand  or  other  materials  that  do  not 
stand  a  high  temperature  well  or  are  not  very  tenacious  when 
heated  are  used,  a  layer  of  fire  clay  and  sharp  sand  is  placed 
over  the  lining  material  under  the  tap  hole.  When  the  heat  is 
very  heavy  and  a  large  amount  of  iron  is  drawn  from  one  tap 
hole,  a  split  fire  brick  is  embedded  under  the  tap  hole  to  pre- 
vent cutting  and  insure  a  good  tap  hole  throughout  the  heat. 
The  spout  is  seldom  coated  or  painted  with  blacking  after  it  is 
made  up  or  dried,  but  when  a  friable  material  is  used  for  lining 
it  is  sometimes  coated  with  clay  wash. 

If  the  spout  is  made  with  a  broad,  flat  bottom  the  stream 
takes  a  new  course  every  time  the  cupola  is  tapped,  and  before 
the  heat  is  over  the  spout  is  so  bunged  up  that  the  iron  collects 
in  pools.  A  continuous  stream  cannot,  therefore,  be  main- 
tained the  length  of  the  spout,  and  two  or  more  streams  may 
fall  from  the  end  of  the  spout  at  the  same  time.  To  prevent 
this,  shape  the  lining  to  form  a  small  groove  for  the  stream  in 
the  center  and  keep  it  there  every  tap.  The  quality  of  the 
lining  material  has  a  great  deal  to  do  with  the  condition  of  a 
spout  during  the  running  out  of  a  heat.  The  spout  may  be 
cut  out  in  holes  by  the  stream  and  pools  of  iron  form  in  the 
spout  at  every  tap.  This  is  due  to  the  lining  material  crumb- 
ling and  being  washed  away  by  the  stream.  When  this  does 
not  occur  every  heat  with  the  same  material,  it  is  due  to  the 
material  not  being  properly  mixed ;  but  if  it  does  occur  every 
heat,  it  is  due  to  poor  material.  The  spout  may  become 
choked  or  bunged  up  with  slag  when  no  slag  flows  from  the 
tap  hole  with  the  iron.  This  is  due  to  the  lining  melting  and 
forming  a  slag.  It  is  very  difficult  to  keep  a  spout  in  order 
through  a  long  heat  when  this  occurs,  and  the  lining  material 
should  at  once  be  changed.  Slag  should  be  removed  from  the 
spout  when  very  hot  by  lifting  it  up  with  a  bar,  or  chipped 
away  with  a  sharp  bar  when  quite  cold.  All  attempts  to 
remove  a  tough  semi-fluid  slag  break  up  and  destroy  the  lining. 


CUPOLA   MANAGEMENT.  71 

FRONT. 

The  front  opening  of  the  modern  drop  botton  cupola  is 
made  so  small  that  it  is  not  necessary  to  place  an  apron  or 
breast  plate  over  it  to  hold  the  front  or  breast  in  place,  as  is 
done  with  the  draw  front  cupola.  The  material  used  for  put- 
ting in  the  front  is  generally  the  same  as  is  used  in  making  up 
the  spout.  The  front  is  generally  put  in  after  the  fire  has 
burned  up,  but  some  melters  put  in  the  front  before  lighting, 
and  light  from  the  tuyeres.  Others  make  up  the  tap  hole  and 
half  the  front  with  a  stiff  mixture  of  fire  clay  and  sharp  sand 
before  lighting  up,  and  fill  in  the  other  half  after  the  fire  has 
burned  up.  But  as  a  general  rule  the  entire  front  is  left  open 
to  give  draft  for  lighting,  and  the  front  is  put  in  after  the  fire  is 
burned  up  and  about  ready  for  charging.  This  gives  sufficient 
time  for  drying  it  before  the  blast  is  put  on. 

When  about  to  put  in  the  front  the  ashes  and  dust  are  care- 
fully brushed  from  the  spout  where  the  front  is  to  be  made* 
and  the  spout  and  front  opening  are  wet  all  around  with  water 
or  clay  wash  to  make  the  front  material  adhere  and  insure  a 
good  joint.  A  breast  of  small  pieces  of  coke  is  built  in  front 
of  the  fire,  or  a  small  board  cut  to  fit  the  front,  with  a  notch  in 
the  bottom  for  the  tap  hole,  is  placed  in  front  of  the  fire  to  pre- 
vent the  front  material  from  being  rammed  or  pressed  too  far 
back  into  the  cupola.  A  snlall  iron  bar  or  a  round  wooden  stick 
is  then  laid  in  the  bottom  of  the  spout  to  form  the  tap  hole. 

If  the  front  is  made  of  molding  sand  or  other  material  that  is 
likely  to  crumble  at  the  tap  hole  and  be  cut  away  by  the 
stream  of  iron  or  be  broken  away  by  the  tap  bar,  a  little  fire 
clay  and  sharp  sand,  or  other  refractory  material,  is  placed 
around  the  bar  or  stick  to  form  the  tap  hole.  The  front 
material  of  molding  sand  or  loam  is  then  thrown  in  and 
rammed  solid  against  the  board,  sides,  top  and  bottom  of  the 
opening.  If  the  front  is  made  of  clay  or  sand,  and  worked 
wet,  it  is  made  into  balls  and  pressed  into  place  with  the 
hands.  When  the  opening  has  been  filled  the  front  is  cut 
away  downward  and  inward  from  the  top  and  sides  of  the 


/2  THE   CUPOLA   FURNACE. 

opening  to  the  bar  forming  the  tap  hole,  until  the  tap  hole  is 
not  more  than  I  y2  inches  long.  The  surplus  material  from  the 
front  is  then  removed  from  the  spout,  the  bar  drawn  from  tap 
hole  and  the  front  and  spout  carefully  trimmed  up. 

If  the  spout  lining  and  front  have  been  made  up  with  clay 
and  sand,  or  other  wet  material,  a  wood  fire  is  built  on  the 
spout  to  dry  it  and  the  front.  When  the  spout  and  front  are 
made  up  with  molding  sand  or  loam  they  are  generally  dried 
by  the  flame  from  the  tap  hole  before  stopping  in,  and  an  iron 
plate  is  sometimes  laid  on  top  of  the  spout  to  concentrate  the 
heat  upon  it. 

The  front  is  generally  made  the  full  thickness  of  the  lining 
and  cannot  be  forced  out  by  the  pressure  of  molten  iron  if 
properly  put  in.  When  the  front  material  is  worked  too  wet,  it 
falls  away  from  the  opening  at  the  top  when  drying,  and  the 
opening  must  be  closed  to  prevent  the  escape  of  the  blast.  If 
the  tap  hole  is  made  too  long  the  iron  may  chill  in  it,  and  the 
cupola  cannot  be  tapped  without  cutting  a  new  hole.  This 
makes  very  bad  work,  for  the  iron  is  generally  melted  from  the 
old  tap  hole  by  the  stream  passing  through  the  new  one,  and 
the  two  holes  become  one.  It  is  then  very  difficult  to  stop  in 
or  control  the  flow  of  iron. 

When  the  front  material  is  poor  it  melts  into  a  semi-fluid 
slag  that  settles  down  and  closes  up  the  tap  hole  with  a  tough 
adherent  slag  that  is  difficult  to  remove.  When  this  occurs 
the  tap'  hole  can  only  be  kept  open  by  continually  opening  it 
up  with  a  tap  bar.  The  only  way  to  overcome  this  difficulty 
is  to  use  a  more  refractory  front  material.  Mineral  fluxes 
sometimes  make  a  front  material  fusible  that  is  not  otherwise 
fusible.  WThen  trouble  is  experienced  in  keeping  the  tap  hole 
open  when  using  a  flux,  or  after  one  flux  has  been  substituted 
for  another,  the  composition  of  the  front  material  must  be 
changed  or  another  material  used. 

When  no  board  is  used  and  the  front  material  is  rammed 
back  into  the  fire  until  it  becomes  solid  in  the  front,  the  front 
is  ragged  and  soft  on  the  inside  and  melts  and  makes  a  bad 


CUPOLA   MANAGEMENT.  73 

tap  hole  even  when  the  material  is  good.  A  good  front  or 
spout  lining  can  always  be  made  from  fire  clay  and  sharp  sand 
by  mixing  them  in  right  proportions  for  the  purpose  for  which 
they  are  to  be  used. 

SIZES   OF   TAP    HOLE. 

The  sizes  the  tap  hole  is  made  depends  upon  how  the  iron  is 
to  be  drawn  from  the  cupola.  If  it  is  desired  to  run  a  continu- 
ous stream  from  the  cupola,  the  tap  hole  is  made  small  to  suit 
the  melting  capacity  of  the  cupola.  If  it  is  desired  to  accumu- 
late a  large  body  of  iron  in  the  cupola  and  fill  a  large  ladle 
rapidly  when  the  cupola  is  tapped,  the  hole  is  made  large. 
The  tap  holes  are  made  of  various  sizes  from  5^  inch  to  ij£ 
inches  diameter,  to  suit  the  different  kinds  of  work.  When  it 
is  desired  to  run  a  continuous  stream  it  is  very  desirable  that 
the  tap  hole  should  not  be  cut  and  enlarged  by  the  stream. 
This  is  generally  prevented  by  placing  a  very  refractory 
material  around  the  rod  forming  the  tap  hole.  But  some 
melters  have  a  form  in  which  they  mold  a  tap  hole  from  a  care- 
fully prepared  material  that  will  not  cut  and  dry  it  in  an  oven 
or  on  a  stove.  This  tap  hole  form,  when  thoroughly  dried,  is 
placed  in  position  on  a  split  fire-brick  and  the  front  made  up 
around  it,  which  always  insures  a  regular  sized  hole  throughout 
the  heat. 

LOCATING  THE  TAP  HOLES. 

We  have  already  described  the  manner  of  putting  in  the  front 
and  forming  the  tap  hole,  and  shall  here  only  consider  the  loca- 
tion and  number  of  tap  holes.  The  tap  hole  is  placed  in  the 
side  of  the  cupola  from  which  it  is  most  convenient  to  convey 
the  iron  to  the  work  to  be  poured,  and  it  makes  no  difference  in 
the  working  of  the  cupola  upon  which  side  it  is  placed  if  the 
bottom  is  sloped  to  throw  the  iron  to  the  hole.  One  tap  hole 
is  sufficient  to  run  the  iron  from  any  ordinary  cupola,  but  two  are 
frequently  put  in.  In  some  cupolas  two  fronts  and  tap  holes 
are  put  in  side  by  side  only  a  few  inches  apart,  and  two  spouts 
are  made  up  so  that  the  tap  hole  can  be  kept  in  better  order 


74  THE   CUPOLA   FURNACE. 

for  drawing  off  the  iron.  They  are  tapped  turn  about,  and  in 
case  too  great  a  quantity  of  melted  iron  accumulates  in  the 
cupola  they  are  both  opened  at  one  time.  Two  tap  holes 
placed  in  this  way  can  only  be  worked  for  hand  ladle  work  at 
the  same  time,  and  they  cannot  be  worked  to  advantage  even 
for  that,  for  they  are  so  close  together  the  men  are  in  each 
other's  way.  One  tap  hole  if  properly  made  and  managed 
will  run  off  all  the  iron  a  cupola  will  melt,  and  it  is  poor  cupola 
practice  to  put  in  two  fronts  and  tap  holes  in  this  way. 

Two  tap  holes  are  frequently  placed  in  a  cupola  for  con- 
venience in  carrying  the  iron  from  the  cupola  to  the  molding 
floors.  They  are  generally  placed  on  opposite  sides  of  the 
cupola,  to  save  carrying  the  iron  around  the  cupola  or  from 
one  molding  room  to  another.  Two  tap  holes  are  also  placed 
in  cupolas  to  facilitate  the  removal  of  the  iron  in  hand  ladles. 
Six  4O-pound  hand  ladles  are  all  that  can  be  safely  taken  from 
a  spout  per  minute.  When  more  than  this  number  of  ladles 
are  filled  and  removed  per  minute,  the  men  have  to  move  so 
rapidly  there  is  danger  of  a  clashing  of  ladles  and  spilling  of 
iron,  and  when  a  heavy  stream  once  gets  away  from  the  men 
and  falls  to  the  floor,  it  spatters  and  flies  so  that  it  is  difficult 
to  stop  in  or  again  catch  it.  When  more  than  8  tons  are 
melted  per  hour  in  a  cupola  for  hand  ladle  work,  two  tap  holes 
are  always  put  in.  They  are  placed  in  the  side  of  the  cupola 
that  is  nearest  the  work  to  be  poured,  but  always  at  a  sufficient 
distance  apart  to  admit  of  the  men  catching  at  one  spout  being 
out  of  the  way  of  those  catching  at  the  other. 

SLAG  HOLE. 

A  slag  hole  for  drawing  off  slag  is  sometimes  placed  in  a 
cupola,  but  it  is  not  used  except  when  the  cupola  is  run  be- 
yond the  capacity  to  which  it  can  be  run  successfully  without 
slagging.  The  hole  is  placed  below  the  level  of  the  tuyeres, 
and  when  it  is  desired  to  accumulate  a  large  body  of  molten 
iron  in  a  cupola  the  slag  hole  is  placed  high.  When  the  iron 
is  drawn  from  a  cupola  as  fast  as  melted  the  hole  is  placed  low. 


CUPOLA   MANAGEMENT.  75 

The  opening  through  the  casing  and  lining  is  generally  made 
oval  and  about  3x4x5  inches. 

The  slag  hole  front  when  the  hole  is  placed  high  consists  of  a 
plug  of  the  same  material  used  for  the  tap  hole  front.  The 
plug  is  placed  in  the  outer  end  of  the  opening  and  is  from  2  to 
3  inches  thick.  A  hole  i  inch  diameter  is  made  through  it  for 
a  tap  hole,  and  the  plug  or  front  is  cut  away  from  the  edges  of 
the  casing  to  the  hole  until  the  hole  is  not  more  than  \y2 
inches  long.  When  the  hole  is  placed  low  and  the  slag  per- 
mitted to  flow  throughout  the  heat  after  it  is  opened  the  plug  is 
made  of  loam  or  molding  sand  mixed  with  a  little  blacking  to 
make  it  porous  when  heated,  and  the  plug  is  placed  in  the  hole 
on  the  inside  flush  with  the  lining.  No  tap  hole  is  made 
through  the  plug  when  placed  in  this  way,  and  when  it  is 
desired  to  tap  slag  a  hole  is  cut  through  it  with  a  sharp  pointed 
tap  bar.  This  material  does  not  bake  hard,  and  the  entire 
plug  may  be  cut  out  when  necessary. 

Slag  chills  more  rapidly  in  a  tap  hole  than  iron,  and  is  more 
difficult  to  tap  or  draw  from  a  cupola,  and  when  the  slag  hole 
is  not  properly  arranged  it  cannot  be  drawn  at  all.  If  the  tap 
hole  is  made  small  and  long  the  slag  chills  in  the  hole  and  it  is 
difficult  to  open  the  hole  or  keep  it  open.  When  the  lining  is 
very  thick  it  must  be  cut  away  and  the  hole  made  large  inside 
of  the  front,  or  the  slag  will  chill  in  the  lining  the  same  as  it 
might  in  the  hole  in  the  front.  The  hole  in  the  lining  can  be 
made  6  or  8  inches  diameter  without  injuring  the  lining,  and  a 
hole  of  this  size  will  admit  a  sufficient  quantity  of  slag  to  the 
tap  hole  to  prevent  it  chilling.  There  is  never  any  difficulty 
from  the  slag  chilling  when  the  front  and  tap  hole  are  placed 
flush  with  the  inside  of  the  lining,  for  the  slag  is  kept  hot  and 
fluid  in  the  cupola,  and  may  be  drawn  off  whenever  there  is  a 
sufficient  quantity  in  the  cupola  to  flow  from  it.  It  is  therefore 
better  to  cut  away  the  casing  and  lining,  and  place  the  front 
flush  with  the  inside  of  the  lining. 


76  THE   CUPOLA   FURNACE. 

LIGHTING    UP. 

When  the  cupola  is  small  the  shavings  are  thrown  in  from 
the  charging  door  and  evenly  distributed  over  the  bottom. 
The  wood  is  cut  short  and  split  fine  and  dropped  down,  a  few 
pieces  at  a  time,  and  so  placed  that  the  fire  will  burn  up  evenly 
and  quickly.  When  the  cupola  is  large  the  melter  goes  down 
into  it  and  his  helper  passes  him  down  the  shavings  and  wood 
from  the  charging  door.  The  shavings  are  evenly  spread  over 
the  bottom,  care  being  taken  to  get  plenty  around  the  outside 
to  insure  a  good  light.  A  layer  of  fine,  light  dry  wood  is  then 
laid  ^ver  the  shavings,  and  on  this  a  layer  of  heavier  wood, 
and  so  on  until  the  required  quantity  of  wood  for  lighting  the 
bed  is  placed  in  the  cupola.  Care  is  taken  to  arrange  the 
wood  so  that  it  will  burn  up  evenly  and  quickly.  A  light  dry 
wood  should  be  used,  and  the  pieces  must  not  be  very  large  or 
too  much  time  will  be  consumed  in  burning  them,  and  the  bed 
will  settle  unevenly. 

When  the  wood  has  been  arranged  the  melter  gets  out  and  a 
thin  layer  of  small  coal  or  coke  is  placed  over  the  wood.  The 
bed  fuel  is  then  thrown  in  evenly  over  the  wood.  All  the  bed 
is  put  in  but  a  few  shovelfuls,  which  are  kept  to  fill  up  any 
holes  that  may  be  formed  by  an  uneven  settling.  The  charg- 
ing door  is  then  closed  and  the  shavings  lighted  at  the  front 
opening.  The  tuyere  doors  are  opened  to  give  draft  and  the 
fire  left  to  burn  up.  When  the  wood  is  nearly  burned  out  and 
there  is  a  good  fire  of  hot  coals  at  the  front  and  tuyeres,  the 
melter  generally  puts  in  the  frontspout  and  builds  a  wood  fire 
on  the  spout  to  dry  them.  He  then  looks  in  at  the  charging 
door,  and  if  the  smoke  is  burned  off  and  the  fire  beginning  to 
show  through  the  top  of  the  bed,  he  puts  in  the  remaining 
few  shovels  of  fuel  and  makes  the  top  of  the  bed  as  level  as 
possible.  He  then  closes  all  the  tuyere  doors  but  one  and 
begins  charging  the  iron  into  the  cupola. 

Straw  may  be  used  in  place  of  shavings  for  lighting  up  when 
shavings  cannot  be  procured.  The  wood  should  be  dry  pine 
or  other  light  wood,  and  it  must  not  be  used  in  too  large  sticks 


CUPOLA   MANAGEMENT.  77 

or  the  bed  will  be  burned  too  much  before  the  wood  is  burned 
.out;  and  if  the  iron  is  charged  before  the  wood  is  burned  out, 
it  smokes  and  the  melter  cannot  see  how  to  place  the  iron  or 
fuel.  For  the  same  reason,  hard  or  green  wood  should  not  be 
used  in  lighting  up. 

When  the  bed  burns  up  on  one  side  and  not  on  the  other  in 
a  small  cupola,  the  bed  may  be  burned  up  on  the  other  side 
after  the  blast  is  put  on  and  the  heat  run  off  successfully.  But 
when  the  bed  burns  up  on  one  side  and  not  on  the  other  in  a 
large  cupola  the  bottom  had  better  be  dropped  at  once.  We 
once  had  to  drop  the  bottom  of  a  6o-inch  cupola  before  the 
heat  was  half  off,  for  the  reason  that  the  melter  was  careless  in 
arranging  the  wood  and  lighting  up,  and  charged  the  iron  with 
the  bed  only  burned  up  on  one  side.  He  thought  the  blast 
would  make  it  burn  up  on  the  other  side,  but  it  did  not,  and 
the  heat  was  a  failure.  Never  burn  the  bed  up  to  warm  or 
heat  up  the  cupola,  for  a  cupola  does  not  require  to  be  heated 
before  it  is  charged,  and  the  lining  burns  out  fast  enough  with- 
out wasting  fuel  to  burn  it  out. 

THE  BED. 

Iron  is  melted  in  a  cupola  within  a  limited  space,  known  as 
the  melting  point  or  melting  zone.  The  melting  point  is  the 
highest  point  in  a  cupola  at  which  iron  is  melted  properly,  and 
the  melting  zone  is  the  space  between  the  highest  and  lowest 
point  at  which  iron  melts  properly.  Iron  may  be  melted  to  a 
limited  extent  above  or  below  these  two  points,  but  it  is 
burned,  hardened  and  generally  dull.  The  melting  zone  ex- 
tends across  the  cupola  above  the  tuyeres,  and  is  from  6  to  8 
inches  in  depth.  Its  exact  location  is  determined  by  the 
volume  of  blast  and  the  nature  of  the  fuel  employed  in  melt- 
ing. A  large  volume  of  blast  gives  a  high  melting  point,  and 
a  small  volume  a  low  melting  point.  A  soft,  combustible  fuel 
gives  a  high  melting  point,  and  a  hard  fuel  a  low  melting  point, 
the  blast  being  equal  in  volume  with  both  fuels. 

To  do  good  melting  the  melting  point  must  be  discovered, 


78  THE   CUPOLA   FURNACE. 

and  only  a  sufficient  quantity  of  fuel  placed  in  the  bed  to  bring 
the  top  of  the  bed  up  to  the  melting  point.  When  the  fuel  is 
hard  anthracite  coal,  the  rule  is  to  use  a  sufficient  quantity  of 
coal  in  the  bed  to  bring  the  top  of  the  bed  14  inches  above  the 
top  of  the  tuyeres  when  the  wood  is  burned  out ;  with  hard 
Connellsville  coke  18  inches,  and  with  soft  coke  20  to  25 
inches.  But  the  melting  point  is  varied  by  the  volume  of  blast 
and  these  rules  do  not  always  hold  good.  So  the  melting 
point  in  each  cupola  must  be  learned  to  get  the  best  results 
from  the  cupola. 

To  fitid  the  melting  point  a  bed  is  put  in  according  to  the 
rule  and  iron  charged  upon  it.  If  the  iron  is  a  long  time  in 
coming  down  after  the  blast  is  put  on,  or  the  iron  melts  very 
slowly  during  the  melting  of  the  first  charge,  but  melts  faster 
at  the  latter  end  of  the  charge  and  is  hot,  the  bed  is  too  high 
and  the  iron  is  being  melted  upon  the  upper  edge  of  the  melt- 
ing zone.  Fuel  and  time  are  then  being  wasted,  and  the  fuel 
should  be  reduced  so  as  to  place  the  iron  at  the  melting  point 
when  melting  begins.  If  the  iron  comes  down  quick  but  is 
dull,  or  if  it  comes  slow  and  dull  and  does  not  grow  hotter  at 
the  latter  end  of  the  charge,  the  melting  is  being  done  on  the 
lower  edge  of  the  melting  zone  and  the  quantity  of  fuel  should 
be  increased  to  bring  the  top  of  the  bed  up  to  the  melting 
point.  When  the  top  of  the  bed  is  placed  only  half  way  up 
the  melting  zone  the  iron  comes  down  hot  and  fast,  but  the 
bed  does  not  melt  the  quantity  of  iron  it  should  and  the  latter 
part  of  the  charge  on  the  bed  is  dull.  The  latter  part  of  the 
charge  on  the  bed  when  the  bed  is  the  proper  height  is  also 
dull  if  the  charge  is  too  heavy  for  the  bed,  and  care  must  be 
taken  in  noting  this  point. 

If  by  comparison  with  the  charges  of  iron  in  various  sized 
cupolas  the  charge  on  the  bed  is  found  to  be  light,  the  bed 
should  be  raised  uutil  the  melting  indicates  that  it  is  at  a 
proper  height ;  then  the  weight  of  iron  on  the  bed  may  be  in- 
creased, if  the  charge  is  too  light.  When  raising  or  lowering 
a  bed,  it  should  be  done  gradually  by  increasing  or  decreasing 


CUPOLA   MANAGEMENT.  79 

the  fuel  from  50  to  100  pounds  each  heat  until  the  exact 
amount  of  fuel  required  in  the  bed  is  found.  If  the  changes  in 
the  bed  are  made  gradually  in  this  way,  the  effect  of  the  changes 
upon  the  melting  may  be  observed  more  accurately  and  better 
results  obtained  than  when  a  radical  change  is  made  by  in- 
creasing or  decreasing  the  fuel  in  large  amounts  at  one  heat. 
When  the  amount  of  fuel  is  found  that  brings  the  top  of  the 
bed  to  a  height  that  gives  the  best  results  in  melting,  the  top 
of  the  bed  is  maintained  at  that  point  each  heat. 

When  a  cupola  is  newly  lined  the  diameter  is  decreased  from 
what  it  was  with  the  old  lining,  and  the  weight  of  fuel  in  the 
bed  must  be  decreased  to  bring  the  top  of  the  bed  down  to 
the  melting  point,  and  as  the  lining  burns  out  and  the  cupola 
gets  larger  the  fuel  must  be  increased  to  keep  the  bed  up  to 
the  melting  point.  Trouble  is  often  experienced  in  melting 
after  a  cupola  has  been  newly  lined.  This  is  because  the 
diameter  of  the  cupola  is  reduced  from  6  to  10  inches,  and 
the  bed  and  charges  are  not  changed  to  correspond  with  the 
reduced  size  of  the  cupola.  There  is  never  any  trouble  of  this 
kind  in  foundries  where  a  cupola  book  is  provided  and  a  record 
kept  of  the  melting  from  one  year's  end  to  another,  for  the 
melter  or  foreman  can  look  back  and  see  the  weight  of  the  bed 
and  charges  when  the  cupola  was  newly  lined,  and  the  increase 
made  in  the  weight  as  the  lining  burned  out  and  the  diameter 
increased. 

No  definite  or  even  approximate  weight  can  be  given  of  the 
amount  of  fuel  required  for  a  bed  in  cupolas  of  different 
diameters,  for  the  tuyeres  are  placed  at  such  a  variety  of 
heights  above  the  sand  bottom  that  for  two  cupolas  of  exactly 
the  same  diameter  twice  the  quantity  of  fuel  may  be  required 
for  a  bed  in  one  as  is  required  for  a  bed  in  the  other.  Cupolas 
with  two  or  three  rows  of  tuyeres  require  a  larger  amount  of 
fuel  for  a  bed  than  cupolas  with  but  one  row,  but  the  same  gen- 
eral directions  for  burning  and  managing  the  bed  apply  to  all 
cupolas. 


80  THE   CUPOLA   FURNACE. 


CHARGING. 


The  old  way  and  the  way  still  in  vogue  in  some  localities  of 
stocking,  loading  or  putting  the  fuel  and  iron  into  a  cupola  is 
to  place  a  sufficient  quantity  of  fuel  in  a  cupola  to  fill  it  above 
the  tuyeres.  On  this  fuel  or  bed  are  placed  from  50  to  500 
pounds  of  iron,  according  to  the  size  of  the  cupola,  then  from 
one  to  four  shovels  of  fuel  are  put  in  and  from  50  to  200 
pounds  of  iron,  and  so  on  until  all  the  iron  to  be  melted  is 
placed  in  the  cupola. 

This  way  of  stocking  a  cupola  mixes  the  fuel  and  iron  in  the 
cupola  and  they  come  down  to  the  melting  point  together. 
The  fuel  fills  a  space  that  should  be  filled  with  iron,  and  a 
great  deal  of  the  melting  surface  of  the  cupola  is  lost,  and  the 
cupola's  melting  capacity  reduced  in  proportion. 

The  modern  way  of  stocking  a  cupola  is  to  put  in  the  fuel 
and  iron  in  layers  or  charges.  Each  layer  or  charge  of  fuel  is 
separated  from  the  layer  or  charge  above  and  below  it  by  a 
layer  or  charge  of  iron,  and  each  layer  of  iron  is  separated  by 
a  layer  of  fuel.  This  way  of  stocking  a  cupola  is  known  as 
charging  the  cupola.  When  a  cupola  is  charged  in  this  way 
the  iron  comes  down  to  the  melting  point  in  a  body  extending 
over  the  melting  surface  of  the  cupola,  and  the  entire  melting 
surface  is  utilized.  The  melting  capacity  of  a  cupola  is  about 
one-half  greater  when  charged  in  this  way  than  when  the  fuel 
and  iron  are  mixed,  and  the  consumption  of  fuel  is  also  less. 

The  first  charge  of  iron  is  placed  on  the  bed  at  the  melting 
point.  In  melting  this  charge  of  iron  a  certain  amount  of  fuel 
is  consumed  and  the  top  of  the  bed  settles  down  from  the  top 
of  the  melting  zone  to  the  bottom  of  the  melting  zone.  The 
charge  of  fuel  on  top  of  the  charge  of  iron  that  has  just  been 
melted  settles  with  the  iron  until  it  unites  with  the  bed  and 
places  the  top  of  the  bed  again  at  the  top  of  the  melting  zone, 
ready  to  melt  the  next  charge  of  iron,  and  so  on  with  each 
succeeding  charge  of  fuel  and  iron  throughout  the  heat.  This  is 
the  correct  theory  of  melting  iron  in  a  cupola,  and  the  practice 
that  must  be  followed  to  obtain  the  best  results  from  a  cupola. 


CUPOLA   MANAGEMENT.  8 1 

Now,  having  described  the  theory  of  charging  and  melting, 
let  us  consider  the  practical  working  of  a  cupola  upon  the 
theory.  The  amount  of  iron  placed  upon  the  bed  in  the  first 
charge  and  in  each  charge  through  the  heat  must  be  the  exact 
amount  of  iron  the  fuel  will  melt  while  settling  from  the  melt- 
ing point  to  the  bottom  of  the  melting  zone.  The  amount  of 
fuel  in  each  charge  must  be  the  exact  amount  required  to  raise 
the  bed  from  the  bottom  of  the  melting  zone  to  the  melting 
point.  If  the  charges  of  iron  are  made  too  heavy  the  iron 
comes  dull  at  the  latter  end  of  the  charge  and  hot  at  the  first  of 
the  charge  until  a  few  charges  have  been  melted,  when  it  comes 
dull  all  through  to  the  end  of  the  heat.  When  the  charges  of 
iron  are  too  light  the  iron  comes  hot,  but  there  is  a  stoppage 
in  melting  at  the  end  of  each  charge,  changing  to  continuous 
but  very  slow  melting  as  the  heat  progresses. 

When  the  charges  of  fuel  are  too  heavy  the  iron  melts  slowly 
and  unevenly,  and  if  the  heat  is  a  long  one  it  comes  dull  and  is 
hardened  in  melting.  When  the  charges  of  fuel  are  too  light 
and  the  charges  of  iron  heavy  the  result  is  dull  iron.  When 
the  charges  of  fuel  and  iron  are  both  too  light  the  iron  gener- 
ally comes  hot  but  slowly  throughout  the  heat,  and  the  full 
melting  capacity  of  the  cupola  cannot  be  realized. 

There  is  no  rule  for  making  the  weight  of  the  first  charge  of 
iron  of  any  definite  proportion  to  the  weight  of  the  bed  of 
either  anthracite  coal  or  coke  that  holds  good  in  all  cupolas. 
Manufacturers  of  some  of  the  patent  cupolas  have  such  a  rule 
for  their  cupolas  that  is  approximately  correct,  but  the  tuyeres 
in  different  sizes  of  these  cupolas  are  always  placed  at  the 
same  height  and  about  the  same  amount  of  fuel  is  required  for 
a  bed.  The  bed  will  melt  a  heavier  charge  of  iron  in  settling 
than  the  other  charges  of  fuel,  and  the  first  charge  is  generally 
made  from  one-third  to  one-half  heavier  than  the  subsequent 
charges.  The  weight  of  the  first  charge  of  iron  varies  from 
two  and  one- half  to  four  and  one-half  times  the  weight  of  the 
bed  with  anthracite  coal ;  with  coke  the  weight  of  the  first 
charge  varies  from  one  and  one-half  to  four  and  o^*irttti^£S 
the  weight  of  the  bed.  /$^Wt*^> 

6  f  UNIVERSITY 


82  THE   CUPOLA   FURNACE. 

These  wide  variations  in  the  weight  of  the  first  charge  of 
iron  in  proportion  to  the  weight  of  the  bed  are  largely  due  to 
the  difference  in  the  height  of  tuyeres  and  the  large  amount  of 
fuel  required  for  a  bed  in  a  cupola  with  very  high  tuyeres. 
But  variation  is  also  due  in  many  cases  to  bad  judgment  in 
estimating  the  weight  the  first  charge  should  be.  The  greater 
the  weight  of  the  first  charge  in  proportion  to  the  weight  of 
the  bed,  the  better  the  average  will  be  in  melting,  and  careful 
experiments  should  be  made  with  every  cupola  to  learn  the 
largest  amount  of  iron  it  will  melt  on  the  bed  with  safety,  and 
that  amount  should  always  be  placed  in  the  first  charge. 

There  is  no  rule  for  making  the  weight  of  the  charges  of  fuel 
or  iron  of  any  definite  proportion  to  the  weight  of  the  bed  or 
first  charge  of  iron,  and  the  weight  of  the  charges  of  both  fuel 
and  iron  is  frequently  changed  in  different  parts  of  the  heat, 
to  give  a  hotter  iron  for  some  special  work  or  to  make  the  iron 
run  of  an  even  temperature  through  the  heat.  In  practice,  the 
weight  of  the  charges  of  iron  to  the  charges  of  anthracite  coal 
varies  from  6  to  14  pounds  of  iron  to  the  pound  of  coal.  With 
coke  they  vary  from  6  to  15  pounds  of  iron  to  the  pound  of 
coke.  These  variations  in  the  per  cent,  of  iron  to  fuel  are  due 
in  many  cases  to  the  quality  of  fuel  and  in  many  other  cases  to 
poor  judgment  in  working  the  cupola.  In  all  cases  the  charge 
of  iron  should  be  made  as  heavy  as  the  charge  of  fuel  will  melt 
and  produce  good  hot  iron  for  the  work,  for  this  is  the  only 
way  a  good  per  cent,  of  iron  to  the  pound  of  fuel  can  be 
obtained. 

PLACING   THE    CHARGES. 

The  top  of  the  bed  is  made  as  level  as  it  can  be  before 
charging  the  iron,  and  the  smoke  must  all  have  disappeared 
so  the  melter  can  see  how  to  place  the  charges.  When  the 
cupola  is  very  high  a  few  hundred  of  stove  plate  or  other  light 
scrap  is  placed  upon  the  bed  to  prevent  the  heavy  pieces  of 
pig  or  other  iron  breaking  up  the  fuel  and  settling  down  into 
the  bed  when  thrown  in.  The  pig  should  be  broken  into  short 
pieces  and  placed  in  the  cupola  with  the  end  toward  the  lining. 


CUPOLA   MANAGEMENT.  83 

The  pieces  of  pig  or  other  iron  are  placed  close  together  so  as 
to  utilize  all  the  heat  and  prevent  its  escape  up  the  stack,  and 
each  charge  is  made  as  level  as  it  can  be  on  top.  The  gates 
and  cupola  scrap  are  placed  on  top  of  the  pig  and  are  used  to 
fill  up  holes  and  level  up  the  charge.  Old  scrap  is  generally 
charged  with  the  pig  when  heavy,  and  on  top  of  the  gates 
when  light.  Rattle  barrel  iron  and  gangway  scrap  or  riddlings 
go  in  with  the  gates,  a  few  few  shovels  to  each  charge. 

The  charge  of  fuel  is  distributed  evenly  over  the  charge  of 
iron,  and  the  second  charge  of  iron  is  put  in  the  same  as  the 
first,  and  the  second  charge  of  fuel  the  same  as  the  first,  and 
so  on  until  the  cupola  is  filled  to  the  charging  door.  Charg- 
ing is  then  stopped  and  the  door  closed  until  the  blast  goes  on. 
When  melting  begins  the  stock  begins  to  settle,  and  the  door 
is  opened  and  charging  continued  as  before  until  all  the  iron  to 
be  melted  is  placed  in  the  cupola.  While  charging  is  going 
on  the  cupola  is  kept  filled  to  the  charging  door  to  prevent  the 
gas  igniting  and  making  a  hot  flame  at  the  charging  door, 
which  makes  it  hot  for  the  men  and  difficult  to  place  the 
charges  of  fuel  and  iron  properly.  When  charging  is  finished 
the  charging  door  is  closed  to  prevent  sparks  or  pieces  of 
burning  fuel  being  thrown  upon  the  scaffold. 

When  the  iron  is  all  or  nearly  all  melted  that  has  been 
charged,  and  it  is  discovered  there  is  not  sufficient  iron  in  the 
cupola  to  pour  off  the  work,  more  iron  is  sometimes  charged. 
At  this  stage  of  the  heat  the  stock  is  so  low  in  the  cupola  and 
the  heat  is  so  intense  that  the  cupola  is  in  a  very  bad  condi- 
tion for  resuming  charging  to  melt  more  iron.  It  is  only  a 
waste  of  fuel  to  charge  it  into  the  cupola  at  this  stage  of  the 
heat,  and  the  only  iron  that  can  be  melted  on  the  fuel  already 
in  the  cupola  is  light  scrap,  and  but  a  limited  quantity  of  it. 
When  the  charging  door  is  opened  the  heat  at  the  opening  is 
so  intense  that  the  men  cannot  go  near  it,  and  the  scrap  must 
be  thrown  in  from  a  distance  or  by  standing  alongside  of  the 
cupola  out  of  the  heat  and  throwing  the  iron  around  into  the 
door  on  a  shovel. 


84  THE   CUPOLA   FURNACE. 

Poor  melting  may  be  due  to  bad  charging.  Iron  or  fuel 
should  never  be  dumped  into  a  cupola  from  a  barrow,  for  it  all 
falls  on  one  side  of  the  cupola.  The  iron  generally  lays  where 
it  falls  in  a  pile,  and  the  fuel  rolls  to  the  other  side  of  the 
cupola,  and  good  melting  cannot  be  done  with  the  fuel  on  one 
side  and  the  iron  on  the  other.  This  way  of  charging  is  about 
equal  to  the  old  way  of  mixing  the  fuel  and  iron,  and  only 
about  one-half  of  the  melting  capacity  of  the  cupola  can  be 
realized.  Fuel  should  never  be  emptied  into  a  cupola  from  a 
basket  or  box,  for  it  all  falls  in  one  place  and  cannot  be  spread 
evenly  over  the  charge  of  iron.  To  charge  a  cupola  properly 
the  iron  must  all  be  thrown  in  with  the  hands,  and  the  fuel  with 
a  shovel  or  fork. 

CHARGING    FLUX. 

When  it  is  desired  to  tap  slag,  the  slag-producing  material  or 
flux  is  charged  in  the  cupola  on  top  of  the  iron  and  evenly  dis- 
tributed. The  flux  is  sometimes  put  on  each  charge  of  iron, 
but  generally  about  one-sixth  of  the  heat  is  charged  without 
flux.  After  that,  flux  is  put  in  on  every  charge  of  iron  except 
the  last  one  or  two  charges,  where  it  is  not  required  if  the 
proper  amount  has  been  used  through  the  heat.  The  quantity 
of  flux  required  depends  upon  the  slag-producing  propensity 
of  the  material  used  and  the  condition  of  the  iron  charged,  and 
is  from  30  to  100  pounds  to  the  ton  of  iron  melted.  If  the 
iron  to  be  melted  is  all  clean  iron,  the  amount  of  flux  required 
is  less  than  when  the  iron  is  dirty  scrap  or  a  large  per  cent,  of 
the  heat  is  sprues  and  gates  that  have  not  been  milled  and  are 
melted  with  a  heavy  coating  of  sand  on. 

If  it  is  not  desired  to  tap  slag  and  the  flux  is  used  only  to 
make  a  brittle  slag  in  the  cupola,  it  is  charged  in  small  quanti- 
ties of  from  5  to  10  pounds  to  the  ton  of  iron,  and  is  placed 
around  the  outside  of  the  charge  near  the  lining.  Flux  is 
sometimes  charged  in  a  cupola  in  a  sufficient  quantity  to  pro- 
duce a  large  body  of  slag  through  which  to  filter  the  molten 
iron  and  cleanse  it  of  impurities,  but  not  in  a  sufficient  quantity 
to  admit  of  slag  being  drawn  from  the  cupola.  This  way  of 


CUPOLA   MANAGEMENT.  85 

fluxing  works  very  well  in  a  short  heat,  but  in  a  long  heat  the 
slag  sometimes  absorbs  a  large  amount  of  impurities,  becomes 
overheated  and  boils  up  in  the  cupola  and  fills  the  tuyeres, 
and  when  boiling  the  slag  cannot  be  drawn  from  the  cupola  at 
the  slag  hole  and  the  bottom  generally  has  to  be  dropped. 

BLAST. 

Before  the  blast  is  put  on  the  tuyere  doors  are  all  tightly 
closed  and  luted  to  prevent  the  escape  of  any  of  the  blast  dur- 
ing the  heat,  and  they  should  be  examined  from  time  to  time 
to  see  that  the  luting  has  not  blown  out  and  the  blast  is  not  escap- 
ing. The  blower  is  speeded  up  to  the  full  speed  at  once,  and  the 
full  volume  of  blast  given  the  cupola  from  the  start.  The  old 
way  of  putting  on  the  blast  light  and  increasing  or  decreas- 
ing it  at  different  stages  of  the  heat  has  been  abandoned 
by  practical  foundrymen,  and  the  cupola  is  given  the  same 
blast  from  the  begining  to  the  end  of  the  heat.  This  is  the 
only  way  good  melting  can  be  done  in  a  cupola  charged  in  the 
manner  before  described.  If  the  cupola  does  not  work  properly, 
remedy  the  evil  by  changing  the  charges,  but  never  vary  the 
blast  in  different  parts  of  a  heat  to  improve  the  melting. 

When  the  blast  is  first  put  on,  it  is  indicated  by  a  rush  of 
blast  from  the  tap  hole  and  at  the  charging  door  by  a  volume 
of  dust  passing  up  the  stack.  Then  follows  a  bluish  colored 
gas  which  bursts  into  a  bluish  flame  as  the  stock  settles,  chang- 
ing to  a  yellowish  hot  flame  as  the  stock  sinks  still  lower.  If 
the  stock  is  kept  up  level  with  the  charging  door  in  a  cupola 
of  good  height  the  gas  does  not  ignite,  and  it  is  the  aim  of  the 
chargers  to  keep  the  stock  up  to  this  point  until  they  are 
through  charging.  When  the  blast  is  shut  off  from  a  cupola 
for  any  cause  or  at  the  end  of  the  heat  before  the  bottom  is 
dropped,  one  or  more  of  the  tuyere  doors  are  at  once  opened 
to  prevent  gas  from  the  cupola  passing  into  the  blast  pipe, 
where  it  is  liable  to  explode  and  destroy  the  pipe. 

The  full  consideration  of  the  blast  for  a  cupola  would  take  up 
more  space  than  we  care  here  to  give  to  it  and  would  lead  our 


86  THE   CUPOLA   FURNACE. 

readers  too  far  from  the  subject  of  working  a  cupola.     We  shall 
therefore  leave  it  for  fuller  consideration  under  another  heading. 

MELTING. 

Melting  begins  in  a  cupola  soon  after  the  blast  is  put  on, 
and  the  exact  length  of  time  is  indicated  by  the  appearance  of 
molten  iron  at  the  tap  hole.  When  the  iron  is  charged  two  or 
three  hours  before  the  blast  goes  on,  and  the  bed  is  not  too 
high,  iron  flows  from  the  tap  hole  in  from  three  to  six  minutes 
after  the  blast  is  on.  When  the  iron  is  charged  and  the  blast 
is  put  on,  immediately  iron  appears  at  the  tap  hole  in  from  1 5  to 
20  minutes,  after  the  cupola  is  rilled  if  the  bed  is  not  too  high. 
When  the  bed  is  too  high,  iron  melts  when  the  surplus  fuel  is 
burned  up  and  permits  it  to  come  down  to  the  melting  point, 
and  it  is  very  uncertain  when  melting  will  begin ;  and  it  is  gen- 
erally from  half  an  hour  to  an  hour  before  any  molten  iron 
appears  at  the  tap  hole.  If  iron  does  appear  at  the  tap  hole 
within  15  or  20  minutes  after  the  blast  is  on,  the  bed  is  either 
too  high  or  the  fire  has  not  been  properly  lit,  and  the  bed  is 
not  doing  its  work  efficiently. 

Foundrymen  differ  as  to  the  time  for  charging  the  iron  before 
the  blast  is  put  on.  Some  claim  that  fuel  is  wasted  by  lighting 
the  fire  early  and  charging  the  iron  two  or  three  hours  before 
the  blast  is  put  on,  while  others  claim  fuel  and  power  are  only 
wasted  by  putting  on  the  blast  as  soon  as  the  iron  is  charged. 
We  have  melted  iron  in  both  ways,  and  we  prefer  to  charge  the 
iron  from  two  to  three  hours  before  the  blast  is  on,  except 
when  the  cupola  has  a  very  strong  draft  that  cannot  be  shut 
off,  as  is  sometimes  the  case  when  there  is  no  slide  in  the  blast 
pipe  for  shutting  off  the  blast,  and  as  air  is  supplied  to  the 
cupola  through  the  pipe.  When  iron  is  charged  and  the 
cupola  filled  to  the  charging  door  with  fuel  and  iron,  and 
the  draft  shut  off  from  the  cupola,  the  cumbustion  of  fuel  in 
the  bed  is  very  light  and  the  heat  that  rises  from  it  is  utilized 
in  heating  the  first  charge  of  iron.  When  the  blast  is  put  on, 
this  charge  of  iron  is  ready  to  melt  and  iron  comes  down  in  a 


CUPOLA  MANAGEMENT.  8/ 

few  minutes.  When  the  blast  is  put  on  immediately  after  the 
cupola  is  charged  the  iron  is  cold,  and  time  is  required  to  heat 
it  before  it  will  melt,  and  the  blower  must  be  run  15  or  20 
minutes  before  iron  appears  at  the  tap  hole,  and  the  first  charge 
melts  more  slowly  than  when  the  iron  has  been  heated  before 
the  blast  is  put  on. 

We  think  the  best  way  is  to  put  on  the  blast  about  two  hours 
after  the  charging  begins.  When  the  blast  goes  on,  the  tap 
hole  is  open  and  is  left  open  until  the  iron  melts  and  runs  hot 
and  fluid  from  it.  From  10  to  20  pounds  are  generally  per- 
mitted to  run  from  the  spout  to  the  floor  to  warm  the  spout 
and  insure  the  iron  being  sufficiently  hot  not  to  chill  in  the  tap 
hole  after  stopping  in.  The  first  iron  melted  is  always  chilled 
and  hardened  to  some  extent  by  the  dampness  of  the  sand  bot- 
tom and  spout,  and  when  the  work  is  light  and  poured  with 
hand- ladles,  a  small  tap  of  a  few  ladles  is  made  in  a  few  min- 
utes after  stopping  in,  and  the  iron  used  for  warming  the  ladles 
and  it  is  then  poured  into  the  pig  bed  or  some  chunks.  In 
some  foundries  the  cupola  is  not  stopped  in  at  all  after  the  iron 
comes  down.  The  first  iron  is  used  to  warm  the  ladles,  and  as 
soon  as  the  iron  is  hot  enough  for  the  work  the  molders  begin 
pouring  it.  We  recently  ran  off  a  heat  of  3 1  tons  in  this  way 
from  a  cupola  for  hand-ladle  work  without  using  a  single  bod 
for  stopping  in. 

When  the  iron  is  handled  in  large  ladles  a  tap  is  not  made 
until  a  sufficient  quantity  is  melted  to  fill  a  ladle  or  there  is 
a  sufficient  body  of  iron  in  the  cupola  to  insure  it  not  chilling 
in  the  bottom  of  a  large  ladle  before  another  tap  is  made. 
When  the  blast  blows  out  at  the  tap  hole  after  a  tap  is  made, 
it  indicates  that  the  melted  iron  is  all  out  of  the  cupola  or  the 
tap  hole  is  too  large,  and  the  cupola  should  be  stopped  in 
until  iron  collects  in  the  bottom,  or  the  size  of  the  tap  hole 
should  be  reduced  to  prevent  the  escape  of  the  blast.  The  size 
of  the  tap  hole  is  reduced  when  it  becomes  too  large  to  run  a 
continuous  stream  without  blowing  out,  by  stopping  in  with 
a  bod  of  stiff  clay  and  sand  that  will  not  cut,  and  as  soon 


88  THE   CUPOLA   FURNACE. 

as  the  bod  is  set,  cutting  a  new  tap  hole  through  the  bod  with 
the  tap  bar.  Iron  should  be  melted  hot  and  fast,  and  it 
should  never  be  drawn  from  a  cupola  for  any  kind  of  foundry 
work  if  it  is  not  hot  and  fluid  enough  to  run  stove  plate  or 
other  light  castings.  Iron  is  not  burned  in  a  cupola  by  melt- 
ing it  hot  and  fast,  but  it  is  burned  and  hardened  by  melting 
it  too  high  in  the  cupola  and  melting  it  slow  and  dull. 

Nothing  is  gained  by  holding  molten  iron  in  a  cupola  to 
keep  it  hot,  for  it  can  be  kept  as  hot  in  a  ladle  as  in  a 
cupola,  and  iron  should  be  drawn  from  a  cupola  as  fast  as 
melted  or  as  fast  as  it  can  be  handled  in  pouring  the  work.  If 
we  were  running  a  foundry  we  should  never  stop  in  the  cupola 
except  to  get  enough  iron  to  give  a  gang  of  men  a  hand-ladle 
full  all  round,  or  to  remove  a  large-ladle  from  the  spout. 
When  the  cupola  is  very  small  and  melts  slowly  it  is  sometimes 
necessary  to  stop  in  and  collect  iron  in  the  cupola,  but  it  is  not 
necessary  to  stop  in  a  large  cupola  for  this  purpose.  If  the 
iron  is  all  poured  with  hand-ladles  the  men  should  be  divided 
into  gangs,  with  only  enough  men  in  each  gang  to  take  away 
the  iron  as  fast  as  melted.  If  this  is  not  done  and  there  is 
a  large  number  of  men,  the  ladles  get  so  cold  between  catches 
that  they  chill  the  iron  before  it  can  be  poured,  and  the  melter 
is  blamed  for  not  making  hot  iron. 

The  flow  of  iron  from  the  tap  hole  indicates  how  the  cupola 
is  melting.  If  it  has  been  properly  charged  the  flow  will  be 
even  in  quantity  and  temperature  throughout  the  heat,  except 
in  a  very  long  heat,  when  the  stream  will  get  smaller  and 
the  cupola  not  melt  so  fast  toward  the  end  of  the  heat.  When 
too  much  fuel  is  used  the  iron  melts  slowly  and  grows  dull  as 
the  heat  progresses.  When  the  charges  of  iron  are  too  heavy 
the  iron  is  not  of  an  even  temperature  throughout  the  heat,  but  is 
dull  at  the  latter  end  of  every  charge  and  hot  at  the  beginning 
of  the  next  charge.  When  the  charges  of  fuel  are  too  heavy  the 
iron  melts  very  slowly  at  the  beginning  of  each  charge  and  fast 
at  the  latter  end,  and  if  the  charges  of  iron  are  also  too  heavy 
the  iron  is  dull  at  the  latter  end  of  the  charge.  If  the  cupola 


CUPOLA   MANAGEMENT.  89 

melts  unevenly  it  is  not  being  properly  worked,  and  the  mode 
of  charging  should  be  changed  until  it  does  melt  evenly  from 
the  beginning  to  the  end  of  the  heat. 

POKING   THE   TUYERES. 

When  the  blast  is  first  put  on,  the  fuel  in  front  of  each  tuyere 
is  bright  and  hot,  but  it  is  soon  chilled  and  blackened  by  the 
large  volume  of  cold  blast  passing  in,  and  the  tuyere  presents 
the  appearance  of  being  closed  up  and  admitting  no  air  to  the 
cupola.  The  blast  when  first  put  on  does  not  remove  the  fuel 
and  make  a  large  opening  in  front  of  each  tuyere  to  get  into 
the  cupola,  but  works  its  way  between  the  pieces  of  fuel  in 
front  of  the  tuyeres,  and  these  openings  remain  open  for  the 
passage  of  blast  after  the  fuel  becomes  cold  and  black.  The 
blast,  therefore,  passes  into  the  cupola  just  the  same  as  when 
the  fuel  was  hot,  and  it  is  not  necessary  to  poke  the  tuyere 
with  a  bar  or  break  away  the  cold  fuel  in  front  of  each  tuyere 
to  let  the  blast  into  the  cupola. 

Toward  the  end  of  a  long  heat,  slag  and  cinder  settle  and 
chill  at  the  bottom  of  a  cupola,  and  often  not  only  close  off 
the  blast  at  the  tuyeres,  but  prevent  it  passing  freely  through 
the  stock  and  out  at  the  top.  If  the  tuyeres  are  poked  at  this 
stage  of  the  heat  an  opening  may  be  made  well  into  the  stock. 
But  in  working  the  bar  around  in  forming  this  opening  most  of 
the  natural  passages  the  blast  has  made  for  entering  the  stock 
are  closed  up.  The  new  opening  is  only  a  hole  bored  into  a 
tough  slag  or  cinder  from  which  there  is  no  way  for  the  blast 
to  escape  into  the  stock,  and  less  blast  enters  a  cupola  after  the 
tuyeres  have  been  poked  and  opened  up  than  entered  before. 
The  only  time  a  tuyere  should  be  poked  with  a  bar  is  when 
cinder  or  slag  has  lodged  or  formed  in  front  of  it  in  such  a  way 
as  to  run  a  stream  of  molten  iron  into  the  tuyere.  The  tuyere 
door  should  then  be  opened  and  the  slag  or  cinder  broken 
away  with  a  bar  to  prevent  the  iron  running  into  the  tuyere. 


90  THE   CUPOLA   FURNACE. 

FUEL. 

Theoretically  ten  pounds  of  iron  are  melted  with  I  pound 
of  anthracite  coal,  and  15  pounds  with  a  pound  of  Connells- 
ville  coke.  But  this  melting  is  done  in  the  foundry  office  or 
in  the  mind  of  the  foreman,  and  it  takes  a  little  more  fuel 
to  melt  iron  in  a  cupola  for  foundry  work.  Six  pounds  of  iron 
to  i  of  anthracite  coal  and  8  pounds  of  iron  to  I  of  Connells- 
ville  coke  is  by  practical  foundrymen  considered  good  melting. 
A  little  better  than  this  can  be  done  in  a  full  heat  for  the  size 
of  the  cupola  and  under  favorable  circumstances,  but  in  the 
majority  of  foundries  fewer  pounds  of  iron  are  melted  to  one 
of  fuel  than  the  above  amount. 

It  is  sometimes  necessary  for  the  melter  to  put  in  a  few  extra 
shovelfuls  of  fuel  when  the  bed  has  been  burned  too  much  before 
charging,  or  to  level  up  the  charges  when  two  or  three  men  are 
shoveling  in  fuel  at  the  same  time  and  get  it  uneven.  The 
melter  is  generally  blamed  if  the  iron  from  any  cause  comes 
dull,  and  he  will  generally  put  in  a  few  extra  shovelfuls  of  fuel 
the  next  heat  to  make  it  hot,  and  if  the  iron  does  come  hot  the 
next  heat  the  extra  shovelfuls  are  put  in  every  heat,  but  are  not 
put  on  the  cupola  report.  In  this  way  foundrymen  are  often 
misled  by  the  cupola  report  and  suppose  they  are  melting 
more  pounds  of  iron  to  the  pound  of  fuel  than  they  really  are. 
The  only  way  the  foundry  man  can  know  exactly  how  many 
pounds  of  iron  he  is  melting  to  the  pound  of  fuel  is  to  have  an 
accurate  account  kept  of  the  amount  of  iron  melted  and  com- 
pare it  with  the  amount  of  fuel  bought  and  delivered  for  the 
cupola,  after  deducting  from  it  any  amount  that  may  have  been 
consumed  in  stoves  or  core  ovens. 

We  recently  met  a  foundryman  who  thought  he  was  melting 
14  pounds  of  iron  to  the  pound  of  fuel,  but  when  he  came  to 
compare  the  iron  melted  with  the  fuel  bought  and  delivered  for 
the  cupola  he  found  he  was  only  melting  about  7  pounds  of  iron 
to  the  pound  of  fuel ;  and  about  the  same  results  would  be 
found  in  every  foundry  that  is  claimed  to  be  melting  a  very  large 
per  cent,  of  iron  to  fuel.  There  is  nothing  gained  by  saving  a 


CUPOLA   MANAGEMENT.  91 

few  cents'  worth  of  fuel  in  the  cupola  and  losing  a  dollar's  worth 
of  work  on  the  floor  by  dull  iron,  and  there  is  nothing  gained 
by  using  too  great  a  quantity  of  fuel,  for  too  much  fuel  in  a 
cupola  makes  dull  iron  as  well  as  too  little  fuel. 

Iron  is  not  melted  in  a  cupola  for  the  fun  of  melting  it  or  to 
learn  how  many  pounds  of  iron  can  be  melted  with  a  pound  of 
fuel,  but  is  melted  to  make  castings.  What  the  foundryman 
wants  from  the  cupola  at  the  tap  hole  is  an  iron  hot  and  fluid 
enough  to  make  a  sound  casting,  regardless  of  the  amount  of 
fuel  required  to  produce  it.  As  before  stated,  iron  cannot  be 
melted  hot  and  fast  in  a  cupola  with  either  too  much  or  too 
little  fuel,  and  foundrymen  have  only  to  melt  their  iron  as  hot 
and  fast  as  it  can  be  melted  in  a  cupola  of  the  size  they  are 
using,  to  know  that  they  are  not  using  either  too  much  or  too 
little  fuel  in  melting. 

If  the  foundryman  will  ask  his  neighbor  what  is  the  size  of 
his  cupola,  how  many  tons,  does  he  melt  per  hour,  how  long 
does  it  take  him  to  run  off  a  heat,  he  will  get  a  better  guide  to 
run  his  cupola  by  than  if  he  asks  him  how  many  pounds  of 
iron  he  melts  to  the  pound  of  fuel.  As  soon  as  the  founder 
undertakes  to  imitate  his  neighbor  and  do  faster  melting  or  get 
better  results  from  his  cupola,  he  will  hear  the  old,  old  story 
from  both  melter  and  foreman  :  "  We  haven't  enough  blast." 
More  cupolas  have  too  much  blast  than  too  little,  and  the  ap- 
parent deficiency  of  blast  is  due  in  the  majority  of  cases  to  too 
much  fuel  in  the  cupola  and  the  iron  being  melted  only  on  the 
upper  edge  of  the  melting  zone.  It  does  not  make  any  differ- 
ence how  much  or  how  little  blast  a  cupola  has.  If  it  is  given 
an  even  volume  of  blast  throughout  the  heat,  the  cupola  will 
melt  a  stream  of  iron  of  an  even  size  and  temperature  through- 
out the  heat  except  toward  the  end  of  a  long  heat,  when  the 
stream  may  get  smaller.  If  the  melter  cannot  run  this  kind  of 
a  stream  from  his  cupola  with  an  even  blast,  then  he  is  at  fault, 
and  neither  the  blast,  nor  too  much  fuel,  is  the  cause  of  the  un- 
even melting. 

We  have  watched  the  charging  of  cupolas  in  a  great  many 


92  THE   CUPOLA   FURNACE. 

stove  and  machinery  foundries,  and  as  a  rule  more  fuel  is  con- 
sumed in  making  dull  iron  in  a  machine  foundry  than  is 
consumed  in  making  hot  iron  in  a  stove  foundry.  This  is  simply 
because  hot  even  iron  cannot  be  produced  with  bad  working  of 
a  cupola  and  too  great  a  quantity  of  fuel,  and  the  stove  founder 
must  have  his  cupola  properly  worked  or  he  cannot  use  the 
iron  to  pour  the  work. 

TAPPING    BARS. 

Tapping  bars  are  made  of  round  iron  of  from  ^  to  I  inch 
diameter,  and  are  from  3  to  10  feet  long.  The  hand  bars 
are  made  with  an  oval  ring  at  one  end  to  serve  as  a  handle  for 
rotating  and  withdrawing  the  bar  when  tapping.  The  other 
end  is  drawn  down  to  a  long  sharp  point  for  cutting  away  the 
bod  and  making  the  tap  hole.  The  bars  for  sledging  are  made 
straight  with  a  long  sharp  point  at  one  end.  This  bar  is  only 
used  in  case  the  tap  hole  becomes  so  tightly  closed  that  it  cannot 
be  opened  with  the  hand  bar,  and  seldom  more  than  one  is  pro- 
vided for  a  cupola.  From  three  to  six  hand  bars  are  provided 
for  each  cupola,  and  when  the  ladles  are  all  of  the  same  size 
the  tap  bars  are  all  made  of  the  same  size,  except  one  or  two 
small  ones  which  are  provided  for  clearing  the  hole  of  any  slag 
or  dirt  that  may  be  carried  into  it  by  the  iron. 

When  the  iron  is  melted  for  different  sized  work  and  large 
and  small  ladles  are  used,  the  bars  are  of  different  sizes,  so 
that  a  large  or  small  hole  may  be  made  to  suit  the  tap  to  be 
made  or  ladle  to  be  filled.  The  bars  are  all  straight  except 
when  the  tapping  is  done  from  the  side  of  a  long  spout.  They 
are  then  slightly  curved  near  the  point,  so  that  the  hole  can 
be  made  in  a  line  with  the  spout.  The  bars  are  dressed  and 
pointed  at  the  forge  before  each  heat,  and  are  given  any  shape 
of  point  the  melter  may  fancy.  A  square  point  cuts  away  a 
bod  very  rapidly  when  rotated  and  leaves  a  nice,  clean  hole, 
but  is  very  difficult  to  keep  a  point  square,  for  they  generally 
become  round  after  a  few  taps  have  been  made  and  they  come 
in  contact  with  the  molten  iron  a  few  times.  For  this  reason 
they  are  generally  made  round  at  the  forge. 


CUPOLA   MANAGEMENT.  93 

Some  melters  have  a  short  steel  bar,  with  a  sharp  flat  point, 
which  they  use  for  cutting  away  the  bod  before  tapping,  but 
never  use  it  for  opening  the  hole.  This  they  do  to  remove  the 
greater  part  of  the  bod  from  the  spout  before  tapping,  and  pre- 
vent it  getting  into  the  ladles.  A  hammer  and  an  anvil,  or  an 
iron  block,  should  be  placed  near  the  cupola  for  straightening 
the  points  and  breaking  cinder  or  dross  from  the  bars,  and  a 
rack  should  be  provided  within  easy  reach  of  the  tap  hole, 
in  which  to  place  the  tap  bars  on  end  until  wanted  for  use. 
There  is  nothing  more  slovenly  and  dangerous  about  a  foundry 
than  to  have  the  tap  bars  lying  around  the  floor  when  a 
heat  is  being  run,  and  it  is  just  as  bad  to  set  them  up  against  a 
post  from  which  they  are  all  the  time  falling  down. 

BOD  STICKS. 

Two  kinds  of  bod  stick  are  used  for  stopping  in  a  cupola ; 
The  wood  stick  and  the  combination  wood  and  iron  stick. 
The  wood  sticks  are  octagonal  or  round,  from  I  */2  to  2 
inches  diameter  and  from  5  to  10  feet  long.  They  are  made 
of  both  hard  and  soft  wood  and  about  an  equal  number  of 
each  wood,  as  some  prefer  one  and  some  the  other.  When 
stopping  in,  the  stick  is  held  against  the  bod  in  the  tap  hole 
until  it  sets  in  the  hole,  and  the  stick  generally  takes  fire  from 
the  heat  of  the  spout.  On  this  account  they  soon  become 
small  near  the  ends  and  have  to  be  sawed  off;  for  this  reason 
they  are  always  made  longer  than  necessary  and  sometimes 
larger  in  diameter. 

The  combination  stick  is  of  the  same  diameter  as  the  wood 
stick,  and  from  4  to  TO  feet  long.  An  iron  ring  is  placed 
on  one  end  of  the  stick,  and  a  rod  of  round  iron  of  from  J^ 
to  $/%  inch  diameter  and  I  to  3  feet  long  is  placed  in  the  end 
of  the  stick.  On  the  end  of  the  rod  is  placed  a  round  button 
of  from  \y2  to  2  inches  diameter,  for  carrying  the  bod.  The 
object  of  the  rod  is  to  prevent  the  stick  being  burned  by  the 
heat  of  the  spout  every  time  the  cupola  is  stopped  in,  and  the 
length  of  the  rod  is  made  to  correspond  to  the  length  of 


94  THE   CUPOLA   FURNACE. 

the  spout.  The  ejection  to  the  combination  stick  is  that  the 
button  does  not  carry  the  bod  as  well  as  the  wood  stick,  and 
the  button  and  rod  must  be  wet  every  time  the  stick  is  used  to 
keep  it  cool,  or  the  heat  will  dry  out  the  bod  and  it  will  fall  off. 
This  repeated  wetting  rusts  the  buttom,  and  if  the  edges  come 
in  contact  with  the  molten  iron  it  makes  the  iron  sparkle  and 
fly ;  and  for  this  reason  most  founders  prefer  the  wood  sticks, 
even  at  the  extra  expense  of  keeping  them  up. 

An  iron  rod  and  button  without  the  wood  stick  is  also  used 
in  some  foundries  for  stopping  in,  but  they  were  not  used  by 
our  grandfathers  and  are  not  popular  with  melters.  Three  or 
four  bod  sticks  are  provided  for  each  cupola.  They  are  placed 
on  end  in  a  rack  alongside  of  the  tap  bars,  within  easy  reach 
of  the  tap  hole,  and  a  bod  is  kept  on  each  stick  all  the  time 
the  cupola  is  in  blast. 

BOD    MATERIAL. 

The  bod  is  a  plug  used  for  closing  the  tap  hole  when  it 
is  desired  to  stop  the  flow  of  iron  from  a  cupola,  and  the 
material  of  which  the  bod  is  composed  has  a  great  deal  to  do 
with  the  nice  working  of  the  tap  hole.  When  the  bod  is 
composed  of  fire  clay,  or  largely  of  fire  clay,  it  does  not 
give  up  the  water  of  combination  rapidly,  and  if  a  tap  is 
quickly  made  after  stopping  in,  the  iron  sputters  and  flies  as  it 
comes  out  of  the  hole.  If  the  bod  is  permitted  to  become 
perfectly  dry  it  bakes  so  hard  that  it  cannot  be  cut  away  with 
the  hand  bar,  and  the  heavy  bar  and  sledge  have  to  be  used  to 
make  a  hole  of  the  proper  size.  If  a  friable  sand  is  used  it 
crumbles  easily  before  the  bar  and  a  nice  clean  hole  can  be 
made ;  but  it  does  not  hold  well,  and  if  the  cupola  is  stopped 
in  for  any  length  of  time  the  bod  may  be  forced  out  by  the 
pressure  of  metal. 

Some  of  the  loams  make  an  excellent  bod  that  holds  well 
and  is  easily  cut  away  with  the  point  of  the  bar,  and  leaves  a 
clean  hole.  Some  of  the  molding  sands  also  make  good 
bods  in  their  native  state,  and  there  are  several  materials  that 


CUPOLA   MANAGEMENT.  95 

are  peculiar  to  certain  localities  that  make  good  bods.  When 
a  suitable  material  cannot  be  found  it  must  be  made  by 
mixing  two  or  more  materials.  A  good  bod  is  made  by  mix- 
ing blue  or  yellow  clay  and  molding  sand.  When  these  clays 
cannot  be  procured,  a  good  bod  can  be  made  by  mixing  just 
enough  fire  clay  with  the  molding  sand  to  give  it  a  little  greater 
adhesive  property,  but  not  enough  to  make  it  bake  hard. 
When  a  large  body  of  iron  is  collected  in  the  cupola  before  a 
tap  is  made,  the  bod  material  must  be  strong,  and  bake  in  the 
hole  sufficiently  hard  to  resist  the  pressure  of  the  iron,  and  an 
entirely  different  material  must  be  used  for  this  kind  of  tapping 
than  is  used  when  the  cupola  is  only  stopped  in  for  a  few 
minutes  at  a  time. 

Small  cupolas  from  which  only  a  small  hand  ladle  is  drawn 
before  it  is  stopped  in  also  require  a  different  bod,  for  the  hole 
has  hardly  time  to  clear  itself  before  it  is  stopped  in  again,  and 
if  the  bod  burns  hard  or  sticks  in  the  hole,  the  hole  is  so  hard 
to  open  that  the  small  amount  of  iron  is  chilled  by  the  bar 
and  slow  tapping  before  it  can  be  run  out.  This  kind  of 
cupola  requires  a  bod  that  will  crumble  and  fall  out  as  soon  as 
touched,  or  burn  out  as  soon  as  the  hole  is  opened.  A  nice 
bod  is  made  for  this  kind  of  work  by  mixing  clay,  molding 
sand  and  sawdust  and  making  it  fully  half  sawdust.  Blacking 
or  sea  coal  is  also  mixed  with  bod  material  to  make  it  more 
porous  when  burned  and  crumble  more  readily  when  tapping. 

Horse  manure  was  at  one  time  considered  to  be  one  of  the 
essentials  of  a  good  bod,  but  it  has  been  replaced  by  blacking 
or  sawdust,  and  is  seldom  used.  A  good  bod  should  have 
strength  to  resist  the  pressure  of  molten  iron  in  the  cupola  and 
at  the  same  time  break  away  freely  before  the  iron  and  leave  a 
clean  hole.  Such  a  material  can  be  made  suitable  for  any 
cupola,  no  matter  how  it  is  tapped,  and  a  bod  material  should 
never  be  used  that  requires  the  sledging  tap  bar  to  open  the 
tap  hole. 


96  THE   CUPOLA   FURNACE. 

TAPPING   AND   STOPPING    IN. 

When  the  blast  is  put  on  the  tap  hole  is  always  open,  and 
is  left  open  until  the  iron  melts  and  flows  freely  and  hot  from 
the  hole.  This  is  generally  in  from  5  to  20  minutes  after  the 
blast  is  on.  While  the  melter  is  waiting  tor  the  iron,  he 
arranges  his  tap  bars,  bod  stuff  and  bod  sticks,  and  places  a 
bod  on  each  stick  to  be  ready  for  instant  use.  The  bod 
material  is  worked  a  little  wetter  than  molding  sand  to  make 
it  adhere  to  the  end  of  the  bod  stick  or  button,  but  care  must 
be  taken  not  to  have  it  too  wet  or  it  will  make  the  iron  fly 
when  stopping  in,  and,  furthermore,  the  bod  does  not  hold  well 
when  too  wet.  The  bod  is  made  by  taking  a  small  handful  of 
the  bod  stuff  and  pressing  it  firmly  on  the  end  of  the  stick 
with  the  hand.  The  size  and  shape  the  bod  is  made  depend 
upon  how  the  iron  is  tapped  and  the  size  of  tap  hole.  When 
the  hole  is  small  and  only  stopped  in  for  a  few  minutes  at  a 
time  a  small  bod  stick  is  used,  and  the  bod  made  very  small  and 
shallow  and  only  pressed  into  the  hole  a  short  distance,  so  that 
it  can  be  quickly  broken  away  when  tapping.  When  the  hole 
is  large  or  has  to  be  stopped  in  until  a  large  body  of  iron 
collects  in  the  cupola,  the  bod  is  made  large,  long  and  pointed, 
so  that  it  may  be  pressed  well  back  into  the  hole  and  stay  in 
place  until  removed  with  the  tap  bar. 

The  first  iron  melted  flows  from  the  hole  in  a  small  stream, 
and  generally  chills  in  the  hole  or  spout  and  has  to  be  removed 
with  the  tap  bar ;  but  it  soon  comes  hot  enough  to  clear  the 
hole,  which  is  then  closed,  unless  the  first  iron  is  used  to  warm 
the  ladles  and  the  hole  is  kept  open  through  the  heat.  If  the 
work  is  light,  a  small  tap  is  made  in  a  few  minutes  to  remove 
any  iron  that  has  been  chilled  and  dulled  by  the  dampness  in 
the  sand  bottom.  But  when  the  work  is  heavy  this  tap  is  not 
made  and  the  molders  go  on  with  their  regular  pouring  from 
the  start.  The  tap  is  made  by  placing  the  point  of  the  bar 
against  the  bod  and  giving  it  a  half  forward  and  back  rotation 
and  at  the  same  time  pressing  it  into  the  bod,  or  by  carrying 
the  handle  end  of  the  bar  around  in  a  small  circle  and  at  the 


CUPOLA   MANAGEMENT.  97 

same  time  pressing  it  in.  As  soon  as  the  bod  is  cut  through, 
the  bar  is  run  into  the  hole  once  or  twice  and  worked  around  a 
little  to  remove  any  of  the  bod  that  may  be  sticking  round 
the  sides  of  the  hole.  The  bar  must  always  be  held  in  such  a 
position  as  will  make  the  hole  in  a  line  with  the  spout,  or  the 
stream  will  not  flow  smoothly  and  may  shoot  over  the  sides  of 
the  spout  and  burn  the  men  catching  in. 

When  about  to  stop  in,  the  bod  is  placed  directly  over 
the  stream  close  to  the  tap  hole  and  the  other  end  of  the  stick 
is  elevated  at  a  sharp  angle  from  the  spout.  The  hole  is 
closed  by  a  quick  downward  and  forward  movement  of  the 
stick  that  forces  the  bod  into  the  hole  and  checks  the  stream 
at  once.  The  stick  is  then  held  against  the  bod  for  a  few 
seconds  until  the  force  of  the  stream  is  stopped  and  the  heat 
has  set  the  bod  fast  in  the  hole.  The  part  of  the  bod  that  does 
not  enter  the  hole  is  then  removed  with  the  stick  to  keep  the 
spout  clean,  and  the  stick  is  dipped  in  water  to  cool  it,  and 
another  bod  applied  to  be  ready  for  the  next  time.  There  is  a 
great  knack  in  stopping  in,  that  some  melters  never  acquire. 
They  hold  the  bod  too  far  from  the  hole,  and  attempt  to  push 
it  up,  under  or  through  the  stream ;  they  get  nervous  and  are 
not  sure  of  their  aim  and  strike  the  stream  too  soon,  or  the 
side  of  the  hole,  and  the  iron  sputters  and  flies  in  all  directions. 

The  bod  sticks  are  frequently  made  so  long  and  slender  or 
so  heavy  that  it  is  impossible  to  accurately  place  the  bod,  and 
it  is  sometimes  difficult  to  get  the  cupola  stopped  in  with  these 
long  sticks.  It  is  also  difficult  to  stop  in  when  the  cupola  is 
placed  very  high,  for  the  melter  cannot  get  up  to  place  the 
bod  stick  at  a  proper  angle  for  stopping  in,  and  has  to  run 
the  bod  up  through  the  stream,  in  place  of  cutting  off  the 
stream  with  the  bod.  An  arm  or  bracket  is  sometimes  placed 
over  the  spout  near  the  tap  hole,  when  long  bars  and  sticks 
are  used,  upon  which  to  rest  the  tap  bars  and  bod  sticks  when 
tapping  and  stopping  in.  But  a  better  plan  is  to  construct  a 
movable  platform  that  can  be  placed  alongside  the  spout  for 
the  melter  to  stand  on.  He  can  then  use  short  bars  and  sticks, 
7 


98  THE   CUPOLA   FURNACE. 

and  has  much  better  control  of  the  tap  hole  than  with  the  long 
bars  and  sticks. 

At  the  tap  hole  is  seen  the  skill  of  the  melter  in  the  results 
obtained  from  his  labor.  If  the  bed  has  been  burned  too  much 
the  first  charge  comes  down  fast  and  slack  or  dull.  If  the  bed 
is  too  high  the  first  iron  is  a  long  time  in  coming  down.  If  too 
much  fuel  is  used,  the  iron  melts  slowly  and  is  dull  toward  the 
last  if  the  heat  is  long.  If  the  charges  of  iron  are  too  heavy, 
the  iron  comes  dull  at  the  end  of  each  charge.  If  the  charges 
of  fuel  are  too  large,  there  is  slow  melting  at  the  end  of  each 
charge.  If  the  iron  flows  from  the  tap  hole  with  great  force 
and  is  difficult  to  control,  the  sand  bottom  has  too  much  pitch. 
If  slag  flows  freely  from  the  tap  hole  with  the  iron,  the  hole 
is  too  large  or  the  bottom  has  too  much  pitch.  If  the  spout 
melts,  crumbles  or  chips  off,  the  material  is  poor  or  has  not 
been  properly  mixed.  If  the  tap  hole  cuts  out,  the  material  is 
poor  or  the  tap  hole  has  not  been  properly  made.  If  the 
tap  hole  gums  up  and  cannot  be  kept  open,  the  front  ma- 
terial is  poor  and  is  melted  by  the  heat,  and  it  may  also  be 
melted  by  the  heat  when  it  is  good  if  rammed  soft  and  ragged 
inside.  If  the  tap  hole  cannot  be  opened  without  a  sledge 
and  bar,  the  bod  bakes  too  hard  and  the  material  should  be 
changed.  If  the  bod  does  not  hold,  the  material  is  not  good 
or  the  bod  is  not  put  in  right.  If  the  cupola  does  not  melt 
evenly  throughout  the  heat  and  the  same  every  heat,  it  is  the 
fault  of  the  melter  and  not  of  the  cupola. 

DUMPING. 

As  soon  as  the  molders  are  through  pouring  their  work,  if 
there  is  no  iron  to  be  melted  for  other  purposes,  preparations 
are  at  once  made  for  dumping  the  refuse  from  the  cupola. 
The  blast  is  first  shut  off  by  stopping  the  blower  and  the 
.tuyere  doors  are  at  once  opened  to  prevent  the  escape  of  gas 
from  the  cupola  into  the  blast  pipe,  where  it  might  do  much 
harm.  The  melted  iron  in  the  cupola  is  then  drawn  off  by  the 
cupola  men  and  poured  in  the  pig  bed.  If  there  is  a  lot  of 


CUPOLA   MANAGEMENT.  99 

small  iron  in  the  cupola  that  has  not  been  melted  time  is  given 
it  to  melt  to  save  picking  it  out  of  the  dump,  but  if  there  is  a 
lot  of  pig  or  other  heavy  iron  unmelted  it  is  let  fall  with  the 
dump,  and  the  bottom  is  dropped  as  soon  as  the  melted  iron  is 
drawn  off. 

The  small  props  supporting  the  bottom  are  first  removed 
and  laid  away.  The  main  prop  is  then  removed  by  striking  it 
with  a  long  bar  at  the  top  or  pulling  with  a  hooked  bar  at  the 
bottom,  and  the  instant  it  falls  the  doors  drop.  When  the 
doors  of  a  large  cupola  drop,  the  sand  bottom  and  a  greater 
part  of  the  refuse  of  melting  falls  with  them  and  a  sheet  of 
flame  and  dust  instantly  shoots  out  ten  feet  or  more  from  the 
bottom  of  the  cupola  in  all  directions.  But  the  flame  disap- 
pears in  an  instant  and  the  dust  settles,  revealing  the  white 
hot  dump  in  a  heap  under  the  cupola.  The  cupola  men  then 
throw  a  few  buckets  of  water  on  it  to  chill  the  surface  and 
deaden  the  heat,  and  the  melter  puts  a  long  bar  into  the 
tuyeres  and  tries  to  dislodge  any  refuse  that  may  be  hanging 
to  the  lining  while  it  is  hot.  Small  cupolas  do  not  dump  so 
freely,  and  the  sand  bottom  has  frequently  to  be  started  with  a 
bar  after  the  door  drops.  A  long  bar  must  be  used  for  this 
purpose  and  the  melter  must  be  on  his  guard,  for  the  dump  may 
fall  as  free  as  from  a  large  cupola  the  instant  it  is  started  and  a 
sheet  of  flame  shoots  out. 

Small  cupolas  frequently  bridge  over  above  the  tuyeres,  and 
only  the  sand  bottom  and  refuse  below  the  bridge  is  dumped 
when  the  door  falls.  The  aim  of  the  melter  is  then  to  break 
away  the  bridge  or  get  a  hole  through  it,  so  that  the  cupola  will 
cool  off  in  time  to  be  made  ready  for  the  next  heat.  He  puts 
a  bar  in  at  the  tuyeres  and  breaks  away  small  pieces  at  a  time, 
and  if  there  is  not  a  large  body  of  refuse  in  the  cupola,  a  few 
short  pieces  of  pig  are  thrown  in  from  the  charging  door,  so 
that  they  will  strike  in  the  center  and  break  through  the  bridge. 
This  bridging  and  hanging  up  of  the  refuse  in  a  cupola  when 
only  run  for  a  few  hours  is  entirely  due  to  mismanagement,  for 
any  cupola,  no  matter  how  small  it  may  be,  can  be  run  for  six 


IOO  THE   CUPOLA    FURNACE. 

or  eight  hours  without  bridging  and  be  dumped  clean  if  prop- 
erly worked. 

When  the  dump  falls  from  a  cupola  it  is  a  semi-fluid  mass  of 
iron,  slag,  cinder,  dirt  and  fuel.  This  mass  falls  in  a  heap 
under  the  cupola,  and  if  scattered  or  broken  up  when  very  hot 
it  is  more  readily  wet  down  and  more  easily  removed  when 
cold.  In  some  foundries  a  heavy  iron  hook  or  frame  is  placed 
under  the  cupola  before  dumping  and  is  withdrawn  with  a  chain 
and  windlass  after  the  dump  has  fallen  upon  it  and  been  par- 
tially cooled  with  water  to  harden  it  so  that  the  hook  will  not 
slip  through  it  without  breaking  it  up  and  scattering  it.  In  other 
foundries  it  is  scattered  with  a  long  rake  or  hook  worked  by 
hand.  In  pipe  foundries  two  or  three  short  lengths  of  con- 
demned pipe  are  placed  under  the  cupola  before  dumping,  and 
the  dump  is  broken  up  by  running  a  bar  into  the  pipe  and  lift- 
ing it  up  after  the  dump  has  been  slightly  cooled.  But  in 
a  great  many  foundries  where  the  dump  is  small  or  where  there 
is  plenty  of  room  to  remove  it  when  cold  it  is  let  lie  as  it  falls 
and  is  wet  down  by  the  cupola  men,  or  a  few  buckets  of  water 
are  thrown  on  by  the  cupola  men  to  deaden  it,  and  it  is  left  for 
the  watchman  to  wet  down  during  the  night.  Care  must  be 
taken  not  to  put  on  too  much  water,  or  the  floor  under  the  cupola 
will  be  made  so  wet  that  there  will  be  danger  of  the  dump  ex- 
ploding when  it  falls  upon  it  the  next  heat. 

REMOVING   THE   DUMP. 

A  number  of  plans  have  been  devised  for  removing  the  dump 
from  under  the  cupola.  Iron  cars  or  trucks  have  been  con- 
structed to  run  under  the  cupola  and  receive  the  dump  as  it 
falls,  but  they  cannot  be  used  unless  there  is  sufficient  room  for 
the  doors  to  swing  clear  of  the  car,  and  few  cupolas  are  so  con- 
structed. The  dump  must  be  removed  from  the  car  when  hot 
to  avoid  heating  and  injuring  the  car,  and  considerable  room  is 
required  for  handling  the  car  after  it  is  taken  from  under  the 
cupola.  For  these  reasons  cars  are  seldom  used.  Iron  crates 
have  been  made  to  set  under  the  cupola  and  receive  the  dump 


CUPOLA   MANAGEMENT.  IOI 

and  be  swung  out  with  the  crane,  but  they  get  fast  under  the 
cupola  and  are  soon  broken,  and  it  is  almost  as  much  work  to 
handle  the  dump  from  the  crate  as  it  is  from  under  the  cupola. 
A  number  of  other  plans  have  been  tried,  but  the  dump  must 
be  picked  over  by  hand,  and  it  is  as  cheap  to  pick  it  over  at 
the  cupola  and  remove  it  in  wheelbarrows  as  by  any  way  that  has 
yet  been  devised.  The  dump  is  broken  up  with  sledge  and  bar 
when  cold  and  picked  over.  The  large  pieces  of  iron  are 
picked  out  and  thrown  in  a  pile  for  remelting.  The  coke  is 
thrown  in  a  pile  to  be  taken  to  the  scaffold  or  core  oven  furnace. 
Anthracite  coal  that  has  passed  through  a  cupola  and  been  sub- 
jected to  a  high  heat  will  not  burn  alone  in  a  stove  or  core  oven 
furnace,  and  it  is  very  doubtful  if  it  produces  any  heat  when 
mixed  with  other  coal  and  again  put  in  the  cupola,  and  only  the 
large  pieces  are  picked  out,  if  any. 

The  cinder,  slag  and  other  refuse  are  shoveled  into  a  wheel- 
barrow and  taken  to  the  rattle-barrels  or  dump.  If  the  sand 
bottom  is  to  be  used  over  again  it  is  riddled  out  in  a  pile  and 
wetted.  If  not,  it  is  removed  with  the  cinder  and  slag.  As 
soon  as  the  bulk  of  the  dump  is  removed  the  melter  goes  into 
the  cupola  and  breaks  down  the  ring  of  cinder  over  the  tuyeres 
and  chips  off  any  that  may  be  adhering  to  other  parts  of  the 
lining.  The  dump  is  then  all  removed  and  the  floor  around  the 
cupola  is  cleaned  up  preparatory  to  daubing  up.  Nothing  is 
done  with  the  dump  after  it  is  taken  from  the  cupola  but  to  re- 
cover the  iron  from  it.  This  is  done  in  two  ways,  by  picking  it 
over  or  milling  it.  The  iron  is  often  of  the  same  color  as  the 
dump,  and  so  mixed  with  it  that  it  is  almost  impossible  to  re- 
cover it  all  by  picking  unless  a  great  deal  of  time  and  pains  be 
taken ;  and  it  is  cheaper  to  throw  out  only  the  pieces  of  pig 
and  shovel  all  the  remainder  into  the  tumbling  barrels,  where 
it  is  separated  in  a  short  time  and  all  the  iron  recovered  that  is 
worth  recovering. 

CHIPPING  OUT. 

Before  going  into  the  cupola  to  chip  it  out  the  melter  slushes 


102  THE   CUPOLA   FURNACE. 

one  or  two  buckets  of  water  around  the  lining  from  the  charging 
door  to  lay  the  dust.  He  then  goes  in  from  the  bottom  if  he 
can  get  in,  but  if  the  cupola  is  so  badly  bridged  that  he  cannot 
get  up  into  it  he  takes  a  long  bar  and  endeavors  to  break  down 
the  bridge  from  the  charging  door,  or  goes  down  into  it  from  the 
charging  door,  and  with  a  heavy  bar  or  sledge  breaks  it  down. 
As  soon  as  he  gets  a  hole  through  large  enough  to  work  in,  he 
goes  down  through  it  and  with  a  sledge  or  heavy  pick  breaks 
down  the  shelf  of  slag  and  cinder  that  always  projects  from  the 
lining  over  the  tuyeres.  He  then  takes  a  sharp  pick  and  trims 
off  all  projecting  lumps  of  cinder  and  slag  and  gives  the  lining 
the  proper  shape  for  daubing  up.  It  is  not  necessary  or  advis- 
able to  chip  off  all  the  cinder  and  adherent  matter  down  to  the 
brick,  for  the  cinder  stands  the  heat  equally  as  well  as  new 
daubing,  and  in  some  cases  better.  But  all  soft  honeycombed 
cinder  should  be  chipped  off,  and  all  projections  of  hard  cinder 
that  are  likely  to  interfere  with  the  melting  or  tend  to  cause 
bridging  should  be  removed. 

Some  melters  have  a  theory  that  to  prevent  iron  running  into 
the  tuyeres  they  must  have  a  projection  or  hump  on  the  lining 
over  the  tuyeres,  and  they  let  the  cinder  build  out  from  3  to  6 
inches  thick  and  6  to  12  inches  deep  at  the  base.  These  humps 
tend  rather  to  throw  iron  into  the  tuyere  than  to  keep  it  out, 
for  the  fuel  becomes  dead  under  the  hump  and  the  iron  in  its 
descent  strikes  the  hump  and  follows  it  around  into  the  tuyere. 
They  also  form  a  nucleus  for  bridging.  The  refuse  of  melting 
as  it  settles  lodges  upon  these  humps  and  is  chilled  by  the  blast. 
A  small  cupola  with  these  humps  over  the  tuyeres  will  not  work 
free  for  more  than  an  hour,  while  the  same  cupola  with  the 
humps  removed  and  the  lining  straight  would  work  free  for  two 
hours  and  dump  clean.  They  also  interfere  with  the  melting 
and  in  large  cupolas  cause  bridging.  All  humps  that  form  on 
the  lining  above  the  melting  point  from  bad  charging  or  other 
causes  should  be  removed,  for  they  hang  up  the  stock  and  re- 
tard melting. 

The  cupola  picks  generally  used  are  entirely  too  light  for  the 


CUPOLA   MANAGEMENT.  1 03 

work  to  be  done  with  them,  and  the  handles  are  not  firm  enough. 
When  the  melter  strikes  a  blow  he  cannot  give  the  pick  force 
enough  to  cut  away  the  point  desired  and  the  handle  gives  in  the 
eye,  so  that  the  pick  glances  off  and  cannot  be  held  to  the  work. 
Repeated  blows  with  a  light  pick  turn  the  edge  and  render  the 
pick  worthless  and  the  melter  has  to  do  two  or  three  times  the 
work  really  necessary  in  chipping  out  the  cupola,  and  then  he 
does  not  get  it  right.  What  the  melter  wants  is  a  heavy  pick 
with  a  firm  handle.  Then  he  can  hold  the  pick  where  he 
strikes  and  prevent  it  glancing  off.  He  can  strike  a  blow  that 
will  cut  away  the  cinder  at  one  stroke  and  not  jar  and  injure 
the  lining  nearly  so  much  as  he  would  by  repeated  blows  with 
a  light  dull  pick.  The  melter  should  be  provided  with  three 
picks  made  of  the  best  steel,  weighing  4,  6  and  8  pounds  each. 
They  should  be  furnished  with  iron  handles  solidly  riveted  in, 
or  should  be  made  with  large  eyes  for  strong  wood  handles. 
The  picks  should  be  dressed,  tempered  and  ground  as  often  as 
they  get  the  least  bit  dull. 

DAUBING. 

After  the  cupola  is  chipped  out  the  lining  is  repaired  with  a 
soft  plastic  adhesive  material  known  as  daubing,  with  which  all 
the  holes  that  have  been  burned  in  the  lining  are  filled  up  and 
thin  places  covered,  and  the  lining  given  the  best  possible  shape 
for  melting  and  dumping.  There  are  a  number  of  substances 
used  for  this  purpose,  some  of  which  are  very  refractory,  and 
others  possess  scarcely  any  refractory  properties  whatever  and 
are  not  at  all  suitable  for  the  purpose.  Molding  sand  is  fre- 
quently used  for  a  daubing.  It  is  easily  and  quickly  wet  up 
and  mixed,  is  very  plastic  and  readily  put  on,  but  possesses 
none  of  the  properties  whatever  requisite  to  a  good  daubing. 
It  crumbles  and  falls  off  as  soon  as  dry  in  exposed  places,  and 
a  lining  cannot  be  shaped  with  it.  Furthermore,  when  put  on 
in  places  from  which  it  is  not  dislodged  in  throwing  in  the  stock, 
it  melts  and  runs  down  and  retards  the  melting  by  making  a 
thick  slag  that  is  readily  chilled  over  the  tuyeres  by  the  cold 
blast. 


104  THE   CUPOLA   FURNACE, 

Some  of  the  yellow  and  blue  clays  are  very  adhesive  and  re- 
fractory, and  make  good  daubing  alone  or  when  mixed  with  a 
refractory  sand.  Ground  soapstone  and  some  of  the  soapstone 
clays  from  coal  mines  make  excellent  daubing.  But  probably 
the  best  and  most  extensively  used  is  that  composed  of 
fire  clay  and  one  of  the  silica  sands  known  under  various 
names  in  different  sections  of  the  country,  and  which  we  shall 
designate  sharp  sand.  Fire  clay  is  very  plastic  and  adhesive 
when  wet,  but  shrinks  and  cracks  when  dried  rapidly.  Sharp 
sand  alone  possesses  no  plastic  or  adhesive  properties  whatever 
and  expands  when  heated.  When  these  two  substances,  in  ex- 
actly the  right  proportions,  are  thoroughly  mixed,  they  make 
a  daubing  that  is  very  plastic  and  adhesive,  does  not  crack  in 
drying,  neither  expands  nor  shrinks  to  any  extent  when  heated, 
and  resists  the  action  of  heat  as  well  as  fire-brick  in  a  cupola. 
When  not  evenly  mixed  the  fire  clay  cracks  and  the  sand  ex- 
pands and  falls  out  of  the  clay  when  heated,  making  an  uneven 
and  uncertain  daubing. 

Fire  clay  absorbs  water  very  slowly,  and  it  requires  from  12 
to  24  hours'  soaking  before  it  becomes  sufficiently  soft  to  be 
thoroughly  and  evenly  mixed  with  the  sand.  A  large  soaking 
tub  should  be  provided  near  the  cupola  and  it  should  be  filled 
with  clay  every  day  after  the  cupola  is  made  up,  and  the  clay 
covered  with  water  and  left  to  soak  until  the  next  heat.  The 
clay  and  sand  cannot  be  evenly  mixed  in  a  round  tub  with  a 
shovel,  therefore  a  long  box  and  a  good  strong  hoe  should  be 
provided  for  the  purpose.  The  amount  of  sand  a  clay  requires 
to  make  a  good  daubing  varies  from  one-fourth  to  three-fourths, 
according  to  the  qualities  of  the  clay  and  sand,  but  generally 
one-half  of  each  gives  good  results.  The  sand  is  added  to  the 
clay  dry,  or  nearly  dry,  and  the  daubing  is  made  as  thick  and 
stiff  as  it  can  be  applied  to  the  lining  and  be  made  to  stick. 
The  more  it  is  worked  in  mixing  the  better,  and  if  let  lie  in  the 
mixing  box  for  a  day  or  two  after  mixing  it  makes  a  better 
daubing  than  if  applied  as  soon  as  prepared. 

Nothing  is  gained  by  using  a  poor,  cheap  daubing,  for   it 


CUPOLA   MANAGEMENT.  1 05 

does  not  protect  the  brick  lining,,  but  falls  off  or  melts  into  a 
thick  tough  slag  which  runs  down  and  chills  over  the  tuyeres 
and  retards  the  melting  by  bunging  up  the  cupola,  and  more 
fuel  and  time  are  required  to  run  off  the  heat.  The  daubing  is 
taken  from  the  mixing  box  on  a  shovel  when  wanted  for  daub- 
ing and  placed  on  a  board  under  the  cupola  if  the  box  is  near 
at  hand.  When  it  is  some  distance  from  the  cupola  the  daub- 
ing is  placed  in  buckets  or  small  boxes  made  for  the  purpose 
and  conveyed  to  the  cupola.  The  parts  of  the  lining  to  be  re- 
paired are  first  brushed  over  with  a  wet  brush  to  remove  the  dust 
and  wet  the  lining  so  that  the  daubing  will  stick  better.  The 
daubing  is  then  thrown  on  to  the  lining  with  the  hands  in  small 
handfuls ;  it  can  be  made  to  penetrate  the  cracks  and  holes 
better  in  this  way  than  in  any  other,  and  stick  better  than  when 
plastered  on  with  a  trowel.  After  the  required  amount  has 
been  thrown  on  in  this  manner,  it  is  smoothed  over  with  a  trowel 
or  wet  brush  and  made  as  smooth  as  possible. 

SHAPING  THE  LINING. 

Daubing  is  applied  to  a  lining  for  two  purposes — viz.,  to 
protect  the  lining  and  to  shape  the  cupola,  the  latter  being  by 
far  the  more  important  of  the  two.  A  great  many  melters 
never  pay  any  attention  to  it,  their  only  aim  being  to  keep  up 
the  lining,  and  they  pride  themselves  on  making  a  lining  last 
for  one,  two  or  three  years.  Nothing  is  gained  by  doing  this 
if  the  melting  is  retarded  by  doing  so  and  enough  fuel  con- 
sumed and  time  and  power  wasted  every  month  to  pay  for  a 
new  lining.  Besides,  a  lining  will  last  just  as  long  when  kept 
in  good  shape  for  melting  as  when  kept  in  a  poor  one,  and  the 
aim  of  the  melter  should  be  to  put  the  lining  in  the  best  possi- 
ble shape  for  melting  and  make  it  last  as  long  as  he  can. 

New  linings  are  made  straight  from  the  bottom  plate  to  the 
charging  door  when  the  cupola  is  not  boshed.  When  it  is 
boshed  the  cupola  is  made  of  a  smaller  diameter  at  and  below 
the  tuyeres,  and  the  lining  is  sloped  back  to  a  larger  diameter 
from  about  6  inches  above  the  tuyeres,  with  a  long  slope 


IO6  THE   CUPOLA   FURNACE. 

of  1 8  or  20  inches.  In  the  straight  cupola,  slag  and  cinder 
adhere  in  every  heat  to  the  lining  just  over  the  tuyeres,  and  if 
not  chipped  off  close  to  the  brick  after  each  heat,  gradually  build 
out  and  in  time  a  hard  ledge  forms  that  is  difficult  to  remove. 
It  furthermore  reduces  the  melting  capacity  of  the  cupola  by 
increasing  the  tendency  to  bridge.  Above  this  point  at  the  melt- 
ing zone  the  lining  burns  away  very  rapidly  and  in  every  heat 
a  hollow  or  belly  is  burned  in  it  at  this  point  that  requires  re- 
pairing. Above  the  melting  zone  the  lining  burns  away  very 
slowly  and  evenly  and  seldom  requires  any  repairing  until  it 
becomes  so  thin  that  it  has  to  be  replaced  with  a  new  one. 

The  cinder  and  slag  that  adhere  to  the  lining  just  over  the 
tuyeres  must  be  chipped  off  close  to  the  brick  every  heat,  and 
the  lining  made  straight  from  the  bottom  plate  to  6  inches 
above  the  top  of  the  tuyeres.  No  projection  or  hump  of  more 
than  y2  or  ^  inch  should  ever  be  permitted  to  form  or  be 
made  over  the  tuyeres  to  prevent  iron  running  into  them,  and 
it  should  be  placed  right  at  the  edge  of  the  tuyere  when  it  is 
thought  necessary  to  make  it.  The  upper  edge  of  the  tuyere 
lining  should  be  made  to  project  out  a  little  further  than  the 
lower  edge,  and  the  brick  lining  should  be  cut  away  a  little 
under  each  tuyere  so  that  molten  iron  falling  from  the  top  of 
the  tuyere  will  fall  clear  of  the  bottom  side  of  the  tuyere  and 
not  run  into  it. 

It  is  not  necessary  or  advisable  to  fill  in  the  lining  at  the 
melting  zone  and  make  it  perfectly  straight,  as  it  is  when  it  is 
new,  for  a  cupola  melts  better  when  bellied  out  at  the  melting 
zone.  It  must,  however,  be  filled  in  to  a  sufficient  extent  for 
each  heat  to  keep  up  the  lining  and  prevent  it  being  burned 
away  to  the  casing.  No  sudden  offsets  or  projections  should 
be  permitted  to  form  or  remain  at  the  upper  edge  of  the  melt- 
ing zone,  for  the  stock  lodges  in  settling  upon  projections  and 
does  not  expand  or  spread  out  to  fill  a  sudden  offset,  and  so 
the  heat  passes  up  between  the  stock  and  lining  and  cuts  away 
the  lining  very  rapidly.  No  sudden  offset  or  hollow  should  be 
permitted  to  form  at  the  lower  edge  of  the  melting  zone  over 


CUPOLA    MANAGEMENT.  IO/ 

the  tuyeres,  for  the  stock  will  lodge  on  it  in  settling  and  cause 
bridging  of  the  cupola.  The  lining  should  be  given  a  long 
taper  from  6  inches  above  the  tuyeres  to  the  middle  of  the 
melting  zone,  and  a  reverse  taper  from  there  to  the  top  of  the 
melting  zone.  The  belly  in  the  lining  should  be  made  of  an  oval 
shape,  so  that  the  stock  will  expand  and  fill  it  as  it  settles  from 
the  top,  and  not  lodge  at  the  bottom  as  it  sinks  down  in  melting. 
As  the  lining  burns  away  above  the  melting  zone  the  straight 
cupola  assumes  the  shape  of  the  boshed  cupola,  and  only  the 
lower  taper  is  given  to  the  melting  zone. 

Daubing  should  never  be  put  on  a  lining  more  than  I  inch 
thick,  except  to  fill  up  small  holes,  and  even  then  small  pieces 
of  fire  brick  should  be  pressed  into  it  to  reduce  the  quantity  of 
daubing  and  make  it  firmer.  All  clays  dry  slowly  and  give  up 
their  water  of  combination  only  when  heated  to  a  high  tem- 
perature. When  daubing  is  put  on  very  thick  it  is  only  skin 
dried  by  the  heat  of  the  bed  before  the  blast  goes  on.  The 
intense  heat  created  by  the  blast  glazes  the  outside  of  the  daub- 
ing before  it  is  dried  through  to  the  lining,  and  as  there  is  no 
way  for  the  moisture  to  escape,  it  is  forced  back  to  the  lining, 
where  it  is  converted  into  steam  and  in  escaping  shatters  the 
daubing  or  tears  it  loose  from  the  lining  at  the  top. 

In  the  accompanying  illustration,  Fig.  19,  is  shown  a  sectional 
view  of  a  cupola  that  we  saw  at  Richmond,  Ind.,  in  1875.  This 
cupola  was  a  small  one,  about  35  inches  diameter  at  the  tuyeres, 
and  the  average  heat  was  about  4  tons.  The  melter  was  a  hard 
working  German,  who  knew  nothing  about  melting  whatever, 
and  his  only  aim  was  to  keep  up  the  lining  in  the  cupola.  With 
this  object  in  view  he  would  fill  in  the  hollow  formed  in  the 
lining  every  heat  at  the  melting  zone  with  a  daubing  of  com- 
mon yellow  elay  and  make  the  lining  straight  from  the  tuyeres 
up.  The  daubing  required  to  do  this  was  from  2  to  4  inches 
thick  all  around  the  cupola,  and  was  put  on  very  wet.  The 
heat  dried  and  glazed  this  daubing  on  the  outside  before  it  was 
dried  through.  There  being  no  way  for  the  water  to  escape,  it 
was  converted  into  steam,  and  in  escaping  from  behind  the 


108  THE   CUPOLA   FURNACE. 

daubing  tore  it  loose  from  the  lining  at  the  top.  The  fuel  and 
stock  in  settling  got  down  behind  the  daubing  and  pressed  it 
out  into  the  cupola  from  the  lining  until  it  formed  a  complete 
bridge,  with  only  a  small  opening  in  the  center  through  which 
the  blast  passed  up  into  the  stock.  Before  the  heat  was  half 

FIG.  19. 


SECTION  THROUGH  BRIDGED  CUPOLA. 

over  all  the  iron  melted  was  running  out  at  the  tuyeres,  and  the 
bottom  had  to  be  dropped.  When  the  cupola  had  cooled  off, 
the  daubing  and  stock  were  found  in  the  shape  shown  in  the 
illustration,  and  when  the  bridge  was  broken  down  it  was  found 
to  be  composed  entirely  of  daubing  that  had  broken  loose  from 
the  lining  in  a  sheet  and  doubled  over. 


CUPOLA   MANAGEMENT.  IOQ 

This  melter  always  had  slow  melting  and  difficulty  in  dump- 
ing. Some  nights  after  dumping  he  would  work  at  the  tuyeres 
with  a  bar  until  eight  o'clock  before  he  got  a  hole  through,  so 
the  cupola  would  cool  off  by  morning.  The  lining  was  not  pro- 
tected by  the  thick  daubing,  but  was  cut  out  more  by  the  re- 
peated bridging  than  if  it  had  been  properly  coated  with  a  thin 
daubing.  We  daubed  this  cupola  properly  and  ran  off  two  heats 
in  it  and  melted  the  iron  in  less  than  half  the  time  usually 
taken,  and  had  no  difficulty  in  dumping  clean. 

The  lining  of  the  boshed  cupola  does  not  burn  out  at  the 
melting  zone  in  the  same  shape  nor  to  so  great  an  extent  as  in 
the  straight-lined  cupola,  and  in  shaping  the  lining  it  is  made 
almost  straight  from  the  top  of  the  slope  to  the  bosh  up  to  the 
charging  door.  The  taper  from  the  bosh  to  the  lining  should 
start  at  6  inches  above  the  top  of  the  tuyeres,  and  should  not 
be  less  than  18  or  20  inches  long,  and  must  be  made  smooth  with 
a  regular  taper  so  that  the  stock  will  not  lodge  on  it  in  settling. 
Should  the  cupola  be  a  small  one  with  a  thick  lining  and  only 
slightly  boshed  and  burn  out  at  the  melting  zone  similar  to  the 
straight  cupola,  it  must  be  made  up  in  the  same  way  as  the 
straight  cupola.  The  great  trouble  with  boshed  cupolas  is  that 
the  melter  does  not  give  a  proper  slope  to  the  taper  from  the 
bosh,  but  permits  a  hollow  to  form  in  the  lining  over  the 
tuyeres,  in  which  the  stock  lodges  in  settling  and  causes  bridg- 
ing out  over  the  tuyeres. 

These  directions  for  shaping  the  lining  only  apply  to  the 
common  straight  and  boshed  cupolas.  Many  of  the  patent 
and  odd-shaped  cupolas  require  special  directions  for  shaping 
and  keeping  up  the  lining  as  it  burns  out,  and  every  manufac- 
turer of  such  cupolas  should  furnish  a  framed  blue  print  or 
other  drawing,  to  be  hung  up  near  the  cupola,  showing  the 
shape  of  the  lining  when  new  and  the  shape  it  should  be  put 
in  as  it  burns  away  and  becomes  thin.  Full  printed  directions 
should  be  given  for  chipping  out  and  shaping  the  lining.  All 
the  improvements  in  cupolas  are  based  on  the  arrangement  of 
the  tuyeres  and  shape  of  the  lining,  and  when  the  lining  gets 


1 10  THE   CUPOLA   FURNACE. 

out  of  shape  the  working  of  the  tuyeres  is  disarranged,  and  the 
cupola  is  neither  an  improved  one  nor  an  old  style,  and  is  gen- 
erally worse  than  either.  More  of  the  improved  cupolas  have 
been  condemned  and  thrown  out  for  want  of  drawings  showing 
the  shape  of  the  lining  and  directions  for  keeping  it  up,  than  for 
any  other  cause. 

RELINING  AND  REPAIRING. 

When  a  cupola  is  newly  lined  the  lining  is  generally  made  of 
the  same  thickness  from  the  bottom  to  the  top  except  when  the 
cupola  is  boshed.  The  casing  is  then  either  contracted  to  form 
the  bosh  or  it  is  formed  by  putting  in  two  or  more  courses  of 
brick  at  this  point.  The  lining  varies  in  thickness  from  4^  to 
T2  inches,  according  to  the  size  of  the  cupola,  the  heavier  lin- 
ings always  being  put  in  large  cupolas.  The  greatest  wear  on 
the  lining  is  at  the  melting  zone,  where  it  burns  away  very 
rapidly.  From  this  point  up  it  burns  away  more  gradually  and 
evenly,  but  the  greatest  wear  is  toward  the  bottom,  where  the 
heat  is  the  greatest,  and  so  a  cupola  gradually  assumes  a  funnel 
shape  with  the  largest  end  down  and  terminating  at  the  melt- 
ing zone,  and  the  lining  is  always  thinnest  at  about  this  point 
when  it  has  been  in  use  for  some  time. 

At  and  below  the  tuyeres  the  destruction  of  the  lining  by 
heat  is  very  slight,  and  the  principal  wear  is  from  chipping  and 
jarring  in  making  up  the  cupola.  At  the  charging  door  the 
principal  wear  is  from  the  stock  striking  the  lining  in  charging. 
In  the  stack  the  lining  becomes  coated  with  sulphides  and 
oxides  and  is  but  little  affected  by  the  heat.  A  stack  lined 
with  good  material  properly  put  in  generally  lasts  the  lifetime 
of  the  cupola.  The  length  of  time  a  cupola  lining  will  last  de- 
pends upon  the  amount  of  iron  melted  and  the  way  in  which  it 
is  taken  care  of,  and  varies  from  six  months  to  three  or  four 
years  when  the  cupola  is  in  constant  use. 

A  lining  burns  away  very  rapidly  at  the  melting  zone,  and  if 
not  repaired  every  heat  would  burn  out  to  the  casing  in  a  few 
heats.  Above  the  melting  zone  it  burns  away  more  slowly  and 
evenly,  and  gets  thinnest  just  above  the  melting  point.  From 


CUPOLA   MANAGEMENT.  1 1  I 

this  point  it  gradually  grows  thicker  up  toward  the  charging 
door,  where  the  wear  is  comparatively  slight.  The  thickness 
of  lining  required  to  protect  the  casing  where  the  heat  is  most 
intense  depends  upon  the  quality  of  the  fire-brick  and  how  the 
lining  is  put  in.  A  lining  of  good  circular  brick  made  to  fit 
the  casing,  and  laid  up  with  a  good,  well-mixed  grout,  remains 
perfectly  solid  in  the  cupola  as  long  as  it  lasts,  and  may  be 
burned  down  to  I  y2  inches  in  thickness,  and  even  less,  for  sev- 
eral feet  above  the  melting  point.  When  the  brick  do  not  fit 
the  casing  and  large  cracks  or  holes  have  to  be  filled  in  with 
grout,  and  daubing  or  the  lining  is  poorly  laid  up,  it  becomes 
shaky  as  it  burns  out  and  in  danger  of  falling  out/ and  it  cannot 
be  burned  down  so  thin  as  when  solid. 

It  is  therefore  cheaper  in  the  long  run  to  get  brick  to  fit  the 
casing  and  have  the  lining  well  put  in.  It  will  then  only  be 
necessary  to  reline  when  the  lining  gets  very  thin  almost  up  to 
the  charging  door.  The  lining  at  the  melting  zone,  where  it 
burns  away  the  fastest,  is  often  taken  out  for  2  or  3  feet  above 
the  tuyeres  and  replaced  with  a  new  one  when  it  is  not  neces- 
sary to  reline  all  the  way  up.  In  repairing  a  lining  in  this  way 
the  same  sized  brick  are  generally  used  as  were  used  in  lining. 
The  lining  has  been  burned  or  worn  away  above  and  below  the 
point  repaired,  and  the  new  lining  reduces  the  diameter  of  the 
cupola  to  the  smallest  at  the  very  part  where  it  should  be  the 
largest.  The  result  is  that  the  new  lining  is  cut  away  faster 
than  any  other  part,  and  after  a  few  heats  it  is  as  bad  as  it  was 
before  the  new  section  was  put  in. 

A  better  way  of  repairing  a  lining  at  the  melting  zone  is  to 
put  in  a  false  lining  over  the  old  lining.  This  is  done  by  putting 
on  a  layer  of  rather  thin  plastic  daubing  over  the  old  lining  and 
pressing  a  split  fire-brick  into  the  daubing  with  the  flat  side 
against  the  lining.  The  brick  are  pressed  into  the  daubing 
close  together  almost  as  soon  as  it  is  put  on,  and  all  the  joints 
are  filled  up  and  the  surface  made  smooth.  A  lining  may  be 
put  in  a  cupola  in  this  manner  all  the  way  around  and  to  any 
height  desired,  or  only  thin  places  may  be  repaired,  which  is 


112  THE   CUPOLA   FURNACE. 

done  without  forming  humps  in  the  lining  that  interfere  with 
the  melting. 

A  split  brick  is  an  ordinary  fire-brick,  only  I  inch  thick  in 
place  of  2  inches,  and  is  now  made  by  all  the  leading  fire-brick 
manufacturers.  We  believe  we  were  the  first  to  repair  a  lining 
in  this  way,  some  20  years  ago.  The  split  brick  could  not  then 
be  procured  from  fire-brick  manufacturers,  and  they  were  made 
by  splitting  the  regular  sized  brick  with  a  sharp  chisel  after 
carefully  nicking  them  all  around.  When  the  regular  split 
brick  cannot  be  procured  they  may  be  made  in  this  way. 
Most  of  the  new  brick  split  very  readily  and  true,  but  bats  from 
old  lining  generally  spall  off  and  are  difficult  to  split.  A  lining 
of  split  brick  can  be  put  in  almost  as  rapidly  as  the  cupola  can 
be  shaped  with  daubing  alone.  The  diameter  of  the  cupola  is 
not  reduced  to  the  same  extent  as  with  a  section  of  new  lining 
put  in  in  the  regular  way,  and  the  best  melting  shape  for  the 
cupola  is  maintained  with  only  a  reduction  in  the  diameter  of 
from  3  to  4  inches.  This  lining,  when  put  in  with  a  good 
daubing  well  mixed,  lasts  as  long  as  an  equal  thickness  of  lin- 
ing put  in  in  the  regular  way ;  and  it  can  be  put  in  at  a  great 
deal  less  expense  for  labor  and  material.  It  is,  however,  worth- 
less if  put  in  with  a  poor,  non-adhesive  and  unrefractory  daub- 
ing. 


CHAPTER  V. 

EXPERIMENTS   IN   MELTING. 

IN  visiting  different  foundries  years  ago,  when  the  manage- 
ment of  cupolas  was  not  so  well  understood  as  at  the  present 
time,  we  found  that  there  were  many  and  different  opinions  held 
by  foundrymen  as  to  the  point  in  a  cupola  at  which  the  melting 
of  iron  actually  took  place.  Some  foundrymen  claimed  that 
melting  was  done  from  the  tuyeres  to  the  charging  door,  others 
that  iron  was  only  melted  in  front  of  the  tuyeres  by  the  blast 
and  flame,  on  a  similar  principle  to  melting  in  an  air  furnace,  and 
still  others  claimed  that  iron  was  only  melted  at  a  short  distance 
above  the  tuyeres.  These  various  opinions  led  to  different 
ways  of  charging  or  loading  cupolas.  In  some  foundries  one 
or  two  hundred-weight  of  iron  were  put  in  on  the  bed,  then  one 
or  two  shovels  of  fuel,  then  more  iron  and  fuel  in  the  same  pro- 
portion, until  the  cupola  was  filled  or  loaded  to  the  charging 
door.  This  way  of  charging  mixed  the  fuel  and  iron  together, 
and  cupolas  were  charged  in  this  way  to  melt  from  the  tuyeres 
to  the  charging  door.  In  other  foundries  from  five  to  twenty- 
hundred  weight  of  iron  were  placed  on  the  bed  and  a  layer  or 
charge  of  fuel  placed  upon  it  to  separate  it  from  a  second  charge 
of  iron  of  a  similar  weight ;  which  was  again  covered  with  a 
second  charge  of  fuel  to  separate  it  from  the  third  charge  of  iron, 
and  the  cupola  in  this  way  filled.  This  charging  was  done  upon 
the  theory  that  a  cupola  only  melted  at  a  short  distance  above 
the  tuyeres.  Foundrymen  who  were  of  the  opinion  that  the 
iron  was  melted  by  the  flame  and  blast  charged  their  cupolas 
in  a  similar  way,  but  made  the  charges  of  iron  light  and  those 
of  fuel  heavier,  using  an  extravagant  amount  of  fuel  for  each 
heat. 

8  H 


114  THE   CUPOLA   FURNACE. 

To  learn  definitely  at  what  point  iron  was  really  melted  in  a 
cupola,  and  also  to  ascertain  something  in  reference  to  a  num- 
ber of  other  points  in  melting,  as  to  which  we  had  found  there 
was  a  wide  difference  of  opinion  among  foundrymen,  we  con- 
structed a  small  cupola  with  a  light  sheet-iron  casing  and  a  thin 
lining,  through  which  tuyere  and  other  holes  could  be  easily  cut 
and  closed  when  not  required.  This  cupola  we  connected  with 
a  Sturtivant  Fan  placed  at  a  short  distance  from  the  cupola. 
The  fan  was  entirely  too  large  for  the  size  of  the  cupola,  but  it 
was  arranged  to  regulate  the  volume  of  blast  supplied  by  in- 
creasing or  decreasing  the  number  of  revolutions  of  the  fan. 
On  the  blast  pipe,  near  the  cupola,  we  placed  a  very  accurate 
steel  spring  air-gauge  to  ascertain  the  exact  pressure  of  blast  in 
each  experimental  heat.  The  cupola  was  eighteen  inches 
diameter  inside  the  lining,  and  we  first  put  in  two  round  tuyeres 
of  four  inches  diameter  and  placed  them  on  opposite  sides  of 
the  cupola,  twenty-four  inches  above  the  bottom. 

The  first  experiments  made  in  melting  in  this  cupola  were  for 
the  purpose  of  learning  at  what  point  in  a  cupola  iron  melted, 
and  at  what  point  it  melted  first.  To  ascertain  these  facts  we 
procured  a  number  of  small  bars  of  No.  I  soft  pig  iron  and 
placed  ten  of  them  across  each  other  in  the  cupola,  six  inches 
apart  from  center  to  center,  and  fastened  the  ends  of  each  pig 
in  the  lining  so  that  they  could  not  settle  with  the  fuel  as  it 
burned  away.  At  the  ends  of  each  pig  we  removed  the  brick 
lining  and  filled  in  the  space  between  the  ends  of  the  pig  and 
casing  with  fire-clay,  and  through  this  clay  and  the  casing 
made  a  small  hole  through  which  the  heat  and  blast  would 
escape  as  soon  as  the  iron  melted  and  fell  out  of  the  lining. 
The  first  bar  of  iron  was  placed  three  inches  above  the  bottom, 
.and  the  others  at  intervals  of  six  inches.  When  they  had  all 
been  put  in  place  the  bottom  door  was  put  up,  a  sand  bottom 
put  in  and  the  fire  started  in  the  usual  way.  As  soon  as  the 
.fire  was  burned  up  the  cupola  was  filled  with  coke  to  the 
charging  door,  which  was  six  feet  from  the  bottom,  and  the 
blast  put  on.  The  fan  was  run  very  slowly  during  the  heat  and 


EXPERIMENTS   IN   MELTING.  I  I  5 

the  air-gauge  showed  less  than  one  ounce  pressure  of  blast  in 
the  pipe  at  any  time  during  the  heat,  and  the  greater  part  of 
the  time  showed  no  pressure  at  all.  We  attributed  the  light 
pressure  of  blast  to  the  fact  that  no  iron  was  placed  in  the 
cupola  but  the  ten  bars  of  pig  iron,  and  the  blast  escaped  freely 
through  the  fuel.  The  pressure  of  blast  would  probably  have 
been  greater  ff  the  fuel  had  been  heavily  weighted  down  with 
charges  of  iron  closely  packed  in  the  cupola.  The  tap  hole 
was  made  small  and  not  closed  during  the  heat,  and  the  iron 
permitted  to  run  out  as  fast  as  melted  and  a  note  made  of  the 
time  at  which  it  melted.  Iron  first  appeared  at  the  tap  hole  in 
three  minutes  after  the  blast  was  put  on,  and  continued  to  flow 
freely  until  one  pig  was  melted,  as  was  shown  by  the  weight  of 
the  iron  when  cold.  The  pig  melted  was  the  one  placed  six 
inches  above  the  top  of  the  tuyeres,  as  indicated  by  the  escape 
of  the  blast  from  the  holes  placed  in  the  casing  at  each  end  of 
the  pig.  After  this  pig  had  melted  there  was  a  cessation  in  the 
flow  of  iron  from  the  tap  hole  for  about  three  minutes,  when  it 
began  to  flow  again  and  flowed  freely  until  another  pig  was 
melted.  The  pig  melted  this  time  was  the  one  placed  twelve 
inches  above  the  tuyeres,  as  indicated  by  the  small  holes  at  the 
ends  of  the  pig.  There  was  then  a  dribbling  of  iron  from  the  tap 
hole  for  a  short  time,  when  it  ceased  altogether ;  but  the  blast  was 
kept  on  until  the  appearance  of  the  flame  at  the  charging  door 
indicated  that  the  fuel  was  all  burned  up,  and  the  bottom  was 
then  dropped. 

When  the  cupola  cooled  off"  it  was  found  that  none  of  the 
four  bars  placed  below  the  tuyeres  had  been  melted  or  bent, 
and  they  showed  no  indications  of  having  been  subjected  to 
an  intense  heat.  The  fifth  bar,  however,  showed  such  indica- 
tions and  was  partly  melted,  but  was  still  in  place.  This  bar 
was  placed  across  the  cupola  almost  on  a  level  with  the  tuyeres, 
and  at  a  point  where  the  blast  met  in  the  center  of  the  cupola 
from  the  two  tuyeres.  The  iron  that  dribbled  from  the  tap 
hole,  as  mentioned  above,  was  melted  from  this  bar.  The 
sixth  and  seventh  bars  had  melted  as  indicated  by  the  escape 


Il6  THE   CUPOLA   FURNACE. 

of  blast  from  the  small  holes  in  the  casing  at  the  ends  of  each 
bar  and  were  entirely  gone.  The  eighth  bar  was  badly  bent 
and  showed  evidence  of  having  been  subjected  to  an  intense 
heat,  but  was  not  melted  at  all.  The  ninth  and  tenth  bars  were 
in  place  and  showed  less  signs  of  having  been  highly  heated 
than  the  eighth  bar.  The  iron  from  the  two  pigs  melted  was  a 
shade  harder  than  when  in  the  pig,  and  the  iron  from  the  pig 
partly  melted  was  two  or  three  shades  harder,  showing  that 
iron  melted  very  slowly  or  burned  off  was  hardened  in  the  pro- 
cess, and  we  afterward  found  this  to  be  correct  in  the  regular 
way  of  charging  a  cupola.  This  heat  showed  that  with  a  light 
blast  the  cupola  melted  only  from  about  the  top  of  the  tuyeres 
to  twelve  or  fourteen  inches  above  the  tuyeres. 

For  the  next  heat  the  two  bars  melted  out  were  replaced  by 
new  ones,  and  the  bent  one  was  also  removed  and  replaced  by 
a  straight  one.  The  cupola  was  made  up  and  fired  in  the  same 
manner  as  in  the  former  heat,  and  filled  with  fuel  to  the  charg- 
ing door.  The  same  sized  tuyeres  were  used  and  the  speed  of 
the  fan  increased  so  as  to  give  a  four-ounce  pressure  of  blast  in 
the  blast  pipe,  as  indicated  by  the  air-gauge.  In  this  heat,  as 
in  the  former  one,  the  iron  placed  below  the  tuyeres  did  not 
melt,  and  the  bars  placed  above  the  tuyeres  at  different  heights 
melted  at  different  times.  The  sixth  bar  placed  six  inches 
above  the  top  of  the  tuyeres  was  the  first  to  melt.  Then  in  a 
few  minutes  later  the  seventh  bar  melted,  and  still  a  few  minutes 
later  the  eighth  bar,  placed  eighteen  inches  above  the  tuyeres. 
These  three  bars  melted  rapidly  after  they  began,  and  were 
melted  within  a  few  minutes  of  each  other.  The  iron  from  the 
first  bar  melted  was  a  little  dull,  but  the  iron  from  the  other 
bars  was  very  hot.  There  was  no  dribbling  of  iron  from  the 
tap  hole  after  the  pigs  were  melted,  as  in  the  former  heat,  and 
one  pig  placed  higher  in  the  cupola,  was  melted  in  this  heat. 
There  was  no  fuel  placed  in  the  cupola  after  the  blast  was  put 
on  and  when  the  fuel  required  to  fill  it  to  the  charging  door, 
or  about  twelve  inches  above  the  top  of  the  last  pig,  was  all 
burned  out,  the  bottom  was  dropped,  and  the  cupola  permitted  to 


EXPERIMENTS    IN    MELTING.  Ii; 

cool  off.  When  we  went  in  to  examine  it,  it  was  found  that  the 
fifth  bar,  placed  opposite  the  tuyeres,  which  had  to  some  extent 
melted  in  the  former  heat,  showed  no  change  and  had  not  been 
subjected  to  so  high  a  temperature  in  this  heat.  The  sixth, 
seventh  and  eighth  bars  had  been  melted  entirely  out,  as  in- 
dicated by  the  escape  of  the  blast  through  the  small  holes  in 
the  casing  at  the  ends  of  each  bar.  The  ninth  bar  was  in  place, 
slightly  bent,  and  showed  indications  of  having  been  subjected 
to  a  higher  temperature  than  during  the  former  heat.  The 
tenth  bar  at  that  point  showed  no  change  from  increase  of  heat. 
From  this  heat  we  learned  that  directly  in  front  of  the  tuyeres 
and  just  above  them,  the  heat  was  decreased  by  a  stronger  or 
greater  volume  of  blast,  and  the  melting  temperature  was  raised 
to  a  higher  level  in  the  cupola ;  for  the  heat  had  been  decreased 
at  the  fifth  bar  to  an  extent  that  prevented  it  from  melting  at 
all,  and  increased  at  the  eighth  bar  to  so  great  an  extent  that  it 
was  readily  melted. 

For  the  next  heat  we  arranged  the  bars  and  cupola  in  exactly 
the  same  way,  and  increased  the  speed  of  the  fan  to  give  an 
eight  ounce-pressure,  as  shown  by  the  air-gauge.  The  melting 
in  this  heat  was  practically  the  same  as  in  the  last  one  just 
described.  We  had  anticipated  that  the  melting  temperature 
would  be  raised  to  a  higher  level  in  the  cupola  by  the  increase 
of  blast,  and  were  very  much  disappointed  when  it  was  found 
that  the  results  were  the  same  as  with  a  four-ounce  pressure  of 
blast.  After  thinking  the  matter  over  for  several  days,  it  oc- 
curred to  us  to  put  on  the  blast  without  charging  the  cupola 
and  test  the  air-gauge  with  different  speeds  of  the  fan.  In  doing 
this  it  was  found  that  with  the  fan  running  at  the  same  speed 
that  showed  eight  ounces  pressure  on  the  gauge  when  the  cupola 
was  in  blast,  the  gauge  showed  six  ounces  pressure  when  the 
cupola  was  not  in  blast.  We  at  once  concluded  that  the  tuy- 
eres were  too  small  to  permit  so  great  a  volume  of  blast  to 
pass  through  them,  and  the  pressure  of  blast  shown  by  the 
gauge  was  due  to  the  smallness  of  the  tuyeres,  and  not  to  the 
resistance  offered  to  the  blast  by  the  stock  in  the  cupola. 


I  I  8  THE   CUPOLA   FURNACE. 

Since  making  this  discovery,  we  have  seen  a  great  many 
cupolas  when  in  blast  show  a  high  pressure  of  blast  on  the  air- 
gauge  when  the  pressure  was  almost  wholly  due  to  the  size  of 
the  tuyeres  and  very  little  blast  was  going  into  the  cupola. 

After  making  the  discovery  that  the  tuyeres  were  too  small 
to  admit  to  the  cupola  the  volume  of  blast  produced  by  the  fan, 
we  placed  two  tuyeres  in  the  cupola,  four  by  six  inches,  laid  flat. 
The  tuyeres  were  made  of  this  shape  to  increase  the  tuyere-area 
and  at  the  same  time  neither  raise  the  top  of  the  tuyere  nor 
lower  the  bottom,  so  that  comparison  of  results  in  melting 
could  be  made  with  the  former  heat  without  rearranging  the 
bars  placed  in  the  cupola. 

For  the  next  heat  we  replaced  the  bars,  melted  out  and 
made  up,  and  charged  the  cupola  as  before  and  ran  the  fan 
at  the  same  speed  that  had  shown  eight  ounces  pressure  on  the 
gauge  with  the  small  tuyeres.  The  result  was  that  the  gauge 
only  showed  a  pressure  of  four  ounces  of  blast.  The  sixth  bar 
placed  six  inches  above  the  tuyeres,  which  had  been  the  first  to 
melt  in  former  heats,  was  not  melted  at  all  in  this  heat,  and  the 
seventh,  eighth  and  ninth  bars  were  melted  in  the  rotation 
named  at  about  the  same  time  apart  as  in  former  heats.  The 
tenth  bar  was  not  melted,  and  none  of  the  bars  below  the 
tuyeres  were  melted.  The  iron  from  the  ninth  bar,  which  was 
placed  twenty-four  inches  above  the  tuyeres  and  was  the  last  to 
melt,  was  accompanied  by  a  good  deal  of  slag  as  it  flowed  from 
the  tap  hole,  and  the  iron  when  cold  was  white  hard,  although 
it  was  No.  I  soft  pig  iron  when  placed  in  the  cupola.  The  slag 
and  hardness  of  the  iron  we  attributed  to  the  strong  or  large 
volume  of  blast  used  in  this  heat,  as  there  had  been  no  harden- 
ing of  the  last  pig  melted  in  former  heats  with  a  lighter  blast. 
But  this  pig  had  remained  in  the  cupola  unmelted  during  the 
three  former  heats  and  been  subjected  to  the  heat  of  the  cupola, 
and  it  was  afterwards  found  that  the  hardness  and  slag  were 
due  to  the  roasting  and  burning  of  the  iron  in  these  heats,  and 
not  to  the  strong  blast  as  at  first  supposed.  -  In  this  heat  the 
melting  temperature  was  raised  to  a  higher  level  in  the  cupola, 
but  only  three  bars  were  melted  as  before  at  a  lower  level. 


OF  THE 


EXPERIMENTS   IN   MELTINGsises*!  19 

For  the  next  heat  we  placed  two  more  tuyeres  in  the  cupola 
at  the  same  level  and  of  the  same  size  as  those  used  in  the  last 
heat,  and  arranged  the  cupola  as  before  with  a  view  to  melting 
the  tenth  or  top  bar.  The  spread  of  the  fan  was  the  same  as  in 
the  last  heat,  in  which  the  gauge  showed  four  ounces  pressure 
of  blast  with  two  tuyeres.  In  this  heat  with  double  the  tuyere- 
area,  the  gauge  indicated  a  pressure  of  about  one  ounce,  show- 
ing that  the  tuyere  was  still  too  small  in  the  last  heat  to  permit 
the  blast  to  escape  freely  from  the  blast-  pipe  into  the  cupola. 
We  were  standing  near  the  spout  during  this  heat  with  our 
watch  and  note-book  in  hand,  waiting  to  time  the  first  appear- 
ance of  iron  at  the  tap  hole  and  thinking  it  was  a  long  time  in 
coming  down,  when  our  assistant  reported  there  was  no  flame 
or  heat  at  the  charging  door,  and  the  fire  must  have  gone  out. 
We  at  once  examined  the  charging  door  and  found  that  noth- 
ing but  cold  air  was  coming  up.  We  then  stopped  the  fan  and 
removed  the  tuyere  pipes,  and  found  there  was  no  fire  in  the 
cupola  at  the  tuyeres.  The  front  was  then  removed  and 
plenty  of  fire  was  found  in  the  bottom  of  the  cupola,  which 
immediately  brightened  up.  The  fire  had  been  well-burned  up 
as  we  supposed,  above  the  tuyeres,  before  the  blast  was  put 
on,  and  it  had  not  been  on  more  than  fifteen  minutes.  We 
were  not  satisfied  with  the  results  in  this  heat,  and  as  the  fire 
showed  signs  of  burning  up  when  the  front  was  out  and  the 
tuyeres  were  opened,  it  was  determined  to  let  it  burn  up  and 
try  it  again  with  the  strong  blast.  After  the  fire  had  burned 
up  until  there  was  a  good  fire  at  the  tuyeres  and  we  were  quite 
sure  the  fuel  was  on  fire  to  eighteen  or  twenty  inches  above 
the  tuyeres,  we  put  on  the  same  volume  of  blast  as  before  and 
watched  the  results  at  the  charging  door.  At  first  the  blast 
came  up  through  the  fuel  quite  hot,  but  the  temperature  grad- 
ually decreased  until  it  became  cold,  and  it  was  evident  that  the 
large  volume  of  blast  had  put  out  the  fire,  and  this  was  found 
to  be  the  case  when  the  tuyere  pipes  were  removed. 

When  the  bottom  was  dropped  there  was  fire  in  the  bottom 
of  the  cupola,  and  the  coke  around  the  tuyeres  showed  that  it 


120  THE   CUPOLA   FURNACE. 

had  been  heated,  but  the  coke  in  the  upper  part  of  the  cupola 
showed  no  signs  of  having  been  to  any  extent  heated. 

The  fuel  used  in  this  heat  was  hard  Connelsville  coke  in  large 
pieces.  Large  cavities  were  formed  under  the  bars  of  iron  sup- 
ported by  the  lining  in  charging.  The  coke  was  not  weighted 
down  with  iron  in  the  cupola,  and  the  blast  escaped  freely 
through  the  crevices  between  the  large  pieces. 

We  afterward  made  a  heat  in  this  cupola  with  the  same  tuyeres 
and  blast,  and  charged  the  cupola  in  the  regular  way.  The 
iron  melted  in  this  heat  was  pig  and  small  scrap,  that  packed 
close  in  the  charges  and  did  not  permit  the  blast  freely  to 
escape  through  the  fuel.  The  gauge  in  this  heat  showed  a  blast 
pressure  of  three  ounces  and  the  fire  was  not  blown  out,  but 
the  cupola  did  not  melt  so  well  as  with  a  less  volume  of  blast, 
and  the  iron  was  harder. 

These  heats  showed  that  iron  is  not  melted  in  a  cupola  by 
the  blast  and  flame  of  the  fuel ;  for  if  it  were,  the  bars  directly 
in  front  and  over  the  tuyeres,  where  the  blast  was  the  strongest, 
would  have  been  melted  first  and  been  the  only  ones  melted. 
But  the  one  in  front  of  the  tuyeres  was  not  melted  by  a  mild 
blast,  and  the  one  just  over  the  tuyeres  was  not  melted  by  a 
strong  blast. 

The  failure  of  the  sixth  and  tenth  bars  to  melt  in  the  same 
heat,  showed  that  iron  is  not  melted  in  a  cupola  all  the  way 
from  the  tuyeres  to  the  charging  door,  as  it  was  years  ago  sup- 
posed to  do  by  most  foundrymen,  when  the  fuel  and  iron  were 
mixed  in  the  cupola  in  place  of  being  put  in  in  separate  charges, 
as  is  now  commonly  done. 

The  raising  of  the  melting  temperature  to  a  higher  level  in 
the  cupola  by  increasing  the  blast,  showed  that  there  is  a 
certain  limited  melting  space  or  zone  in  a  cupola  in  which  iron 
melts,  and  that  this  melting  zone  may  be  raised  or  lowered  by  an 
increase  or  decrease  of  the  volume  of  blast.  However  the  depth 
of  the  melting  zone  is  not  increased  by  a  strong  blast,  but  the 
zone  is  placed  higher  in  the  cupola.  It  was  also  shown  that 
iron  cannot  be  melted  in  a  cupola  outside  of  this  zone,  either 


EXPERIMENTS   IN   MELTING.  121 

above  or  below  it,  for  the  bars  placed  above  and  below  it  were 
not  melted  with  either  a  light  or  a  strong  blast.  The  putting  out 
of  the  fire  in  the  cupola  by  a  very  large  volume  of  blast  and  the 
subsequent  poor  melting  done  with  a  large  volume  of  blast 
when  the  cupola  was  charged  in  the  regular  way,  showed  that 
too  much  blast  may  be  given  to  a  cupola  and  the  iron  thereby 
injured. 

FUEL  UNDER  THE  TUYERES. 

In  the  first  two  heats  it  was  noticed  that  considerable  coke 
fell  from  the  cupola  when  the  bottom  was  dropped,  although 
the  indications  of  the  charging  door  were  that  all  the  fuel  in 
the  cupola  had  been  burned  up.  We  determined  to  learn 
where  this  coke  came  from,  and  in  the  third  heat  we  kept  the 
blast  on  until  the  cupola  was  well  cooled  off,  and  we  then 
turned  a  stream  of  water  into  it  from  a  hose  until  the  fire  was 
out  and  the  cupola  cold.  The  ashes  and  cinder  were  then  re- 
moved from  the  tuyeres,  and  it  was  found  that  there  was  no 
fuel  above  them  except  a  few  small  pieces  that  had  been  buried 
in  the  ashes  and  cinder.  The  bottom  was  let  down  gradually, 
and  the  cupola  found  to  be  filled  with  coke  and  very  little  ashes 
from  the  bottom  to  the  tuyeres. 

The  coke  when  examined  showed  that  it  had  been  heated 
through,  and  was  soft  and  spongy  like  gas-house  coke,  and 
totally  unfit  for  melting  purposes.  When  put  into  the  cupola 
it  was  hard  Ccnnelsville  coke.  We  thought  that  all  the  ash 
found  in  the  coke  was  made  by  the  burning  up  of  the  bed  before 
the  blast  was  put  on,  and  that  the  coke  was  not  consumed  at  all 
after  the  blast  was  put  on  ;  but  we  had  no  means  of  accurately  de- 
termining this  point.  We  afterward  put  a  number  of  peep  holes 
in  the  cupola  at  different  points  below  the  tuyeres  to  observe 
the  action  of  the  fuel  at  this  point.  The  holes  were  arranged 
with  double  slides,  the  inner  one  with  mica  and  the  outer  one 
with  glass.  The  mica  was  not  affected  by  the  heat,  and  could 
be  withdrawn  for  a  few  minutes  and  the  action  of  the  fuel 
observed  through  the  glass  without  the  escape  of  the  blast. 
Through  these  openings  it  was  observed  that  the  fuel  was 


122  THE   CUPOLA   FURNACE. 

always  at  a  white  heat  just  before  the  blast  was  put  on,  but  after 
the  blast  had  been  on  for  a  short  time  it  became  a  dull  red 
and  remained  so  throughout  the  heat.  Molten  iron  could  be 
seen  falling  through  the  fuel  in  drops  and  small  streams.  But 
the  fuel  was  never  seen  to  undergo  any  change  or  to  settle 
down  as  it  would  do  if  it  were  burning  away.  From  these  ob- 
servations it  was  concluded  that  the  fuel  placed  under  the  tuy- 
eres was  not  consumed  during  the  time  the  blast  was  on,  and 
that  the  only  fuel  burned  in  this  part  of  the  cupola  was  that 
consumed  in  lighting  up  before  the  front  was  closed. 

LOW  TUYERES. 

After  the  failure  to  melt  with  the  four  large  tuyeres,  we  placed 
two  tuyeres,  four  by  six  inches,  in  the  cupola,  on  opposite  sides, 
three  inches  from  the  bottom  or  one  inch  above  the  sand 
bottom.  The  bars  were  placed  in  the  cupola  as  before  and 
the  cupola  filled  with  coke  to  the  charging  door,  and  a  four- 
ounce  pressure  of  blast  put  on,  the  same  as  in  the  heat  with 
these  two  tuyeres  when  placed  at  a  higher  level,  namely, 
twenty-four  inches  above  the  bottom.  In  this  heat  three  bars 
were  melted,  but  the  quantity  of  slag  that  flowed  from  the  tap 
hole  with  the  iron  was  so  great  that  we  did  not  know  where  it 
came  from  and  we  were  so  afraid  of  the  tuyeres  being  filled 
with  slag  or  iron,  that  we  failed  to  note  the  time  the  iron  melted 
or  the  points  we  were  looking  for;  but  something  else  was 
learned. 

We  at  first  thought  the  slag  came  from  tuyeres  being  placed 
so  near  the  sand  bottom,  and  when  the  coke  with  which  the 
cupola  had  been  filled  was  burned  out  and  the  heat  over,  we 
took  out  the  front  and  raked  out  the  fuel  and  ash  in  place  of 
dropping  the  bottom,  to  see  how  badly  the  sand  bottom  had 
been  cut  up  by  the  blast.  It  was  found  that  it  had  not  been  cut 
at  all  and  was  as  perfect  as  when  put  in  and  nicely  glazed.  The 
lining  had  not  been  burned  out  to  any  greater  extent  than  in 
former  heats  when  there  was  no  slag,  and  we  were  at  a  loss  to 
imagine  where  the  slag  came  from.  But  when  the  iron  that  had 


EXPERIMENTS    IN   MELTING.  123 

been  melted  in  this  heat  was  examined,  it  was  found  where  the 
slag  came  from.  All  the  pigs  melted  were  placed  in  the  cupola 
at  the  beginning  of  the  experiments  and  had  remained  there 
unmelted  under  the  tuyeres  during  a  number  of  heats,  and  the 
iron  had  been  burned  by  the  fire  in  the  bottom  of  the  cupola 
when  lighting  up  and  during  the  heats.  When  placed  in  the 
cupola  this  iron  was  No.  T  soft  pig,  but  when  melted  it  was  as 
hard  and  brittle  as  glass,  and  fully  two-thirds  of  it  had  been 
burned  up  and  when  melted  converted  into  slag. 

The  results  of  this  heat  were  so  unsatisfactory  that  we  replaced 
the  bars  melted  out  and  repeated  the  experiment.  The  results 
in  this  heat  were  practically  the  same  as  in  the  heat  with  the 
tuyeres  placed  twenty-four  inches  above  the  bottom.  Three 
bars  placed  six,  twelve  and  eighteen  inches  above  the  tuyeres 
were  melted  in  the  same  rotation  and  in  about  the  same  time, 
There  was  no  trouble  with  slag,  and  the  cupola  melted  equally 
as  well  as  when  the  tuyeres  were  placed  twenty-four  inches 
above  the  bottom. 

MELTING  ZONE. 

These  heats  established  the  fact  that  there  exists  a  melting 
zone  in  a  cupola  when  in  blast,  and  that  iron  cannot  be  melted 
in  a  cupola  outside  of  this  zone.  The  location  of  a  melting 
zone  in  a  cupola  is  determined  by  the  tuyeres  and  the  distance 
or  height  of  the  zone  above  the  tuyeres  by  the  volume  of  blast, 
and  the  depth  of  the  zone  by  the  volume  of  blast  and  charging 
of  the  cupola.  In  these  heats  the  melting  zone  was  lowered 
in  the  cupola  twenty-one  inches  by  lowering  the  tuyeres  to  that 
extent  without  making  any  change  in  the  character  of  the  melt- 
ing, and  the  zone  could  have  been  raised  the  same  distance 
without  making  any  differance  in  the  melting.  The  zone  was 
raised  from  one  level  to  another  above  the  tuyeres  by  increasing 
the  volume  of  blast.  In  the  first  heat,  with  a  light  blast,  a  bar 
of  iron  placed  on  a  level  with  the  tuyeres  was  partly  melted, 
and  one  placed  eighteen  inches  above  the  tuyeres  was  highly 
heated  and  almost  ready  to  melt.  Bars  placed  above  and 


124  THE   CUPOLA   FURNACE. 

below  these  two  bars  were  very  little  affected  by  the  heat,  and 
bars  between  them  were  melted,  showing  that  these  two  bars 
were  on  the  edges  of  the  melting  zone,  and  the  zone  had  a 
depth  of  about  eighteen  inches.  In  the  next  heat,  with  a  larger 
volume  of  blast,  the  bar  placed  on  a  level  with  the  tuyeres  was 
not  melted  at  all,  showing  that  it  was  outside  of  the  melting 
zone  and  the  zone  had  been  raised  by  the  stronger  blast.  In 
the  next  heat,  with  a  still  larger  volume  of  blast,  a  bar  placed 
six  inches  above  the  tuyeres  was  not  melted,  showing  that  the 
zone  had  again  been  raised  by  the  volume  of  blast.  In  each  of 
these  heats  a  bar  placed  higher  in  the  cupola  was  melted,  show- 
ing that  the  depth  of  the  zone  remained  about  eighteen  inches 
and  the  entire  zone  was  raised  to  a  higher  level  in  the  cupola, 
we  attributed  the  raising  of  the  zone  by  increasing  the  volume 
of  blast  to  the  fact  that  the  blast  was  cold  when  it  entered  the 
cupola,  and  it  was  necessary  for  the  air  to  pass  through  a 
certain  amount  of  heated  fuel  and  become  heated  to  a  certain 
degree  before  its  oxygen  entered  freely  into  combination  with 
the  carbon  of  the  fuel  to  produce  an  intense  heat;  and  the 
greater  the  volume  of  cold  air,  the  greater  the  amount  of  heated 
fuel  it  must  pass  through  before  it  became  heated.  With  a 
hot  blast  this  would  not  have  been  necessary,  and  the  zone 
would  probably  have  remained  stationary  and  the  depth  of  the 
zone  been  increased.  In  heats  that  were  afterward  made  in  this 
cupola  with  fuel  and  iron  charged  in  the  regular  way,  we  found 
that  the  location  and  depth  of  the  zone  were  somewhat  changed 
by  the  weighting  down  of  the  fuel  with  heavy  charges  of  iron. 
These  tests  were  made  by  carefully  measuring  the  fuel  in  the 
cupola  from  the  charging  door  after  the  fire  was  burned  up  and 
the  fuel  settled,  and  we  took  care  to  have  the  fuel  burned  as 
nearly  alike  in  each  heat  as  possible,  and  to  have  the  fire  show 
through  the  top  of  the  bed  before  iron  was  charged. 

In  a  former  heat,  with  only  bars  in  the  cupola,  a  bar  was 
melted  placed  twenty-four  inches  above  the  tuyeres.  We  placed 
a  bed  of  that  height  in  the  cupola  and  put  a  charge  of  three 
hundred  weight  of  iron  on  it,  and  turned  on  the  same  blast  with 


EXPERIMENTS   IN   MELTING.  125 

which  we  melted  the  bar  at  that  height.  The  blast  was  on  for  half 
an  hour  before  any  iron  melted,  and  the  melting  was  very  slow 
until  about  half  the  charge  was  melted,  when  it  began  to  melt 
faster.  This  indicated  that  the  iron  was  placed  above  the  melt- 
ing zone  and  supported  there  by  the  fuel,  and  the  fuel  had  to 
be  burned  away  before  the  iron  was  permitted  to  come  within 
the  zone  by  the  settling  of  the  stock. 

In  the  next  heat  we  placed  the  top  of  the  bed  two  inches 
lower,  and  in  each  subsequent  heat  two  inches  lower,  until  it 
was  lowered  to  ten  inches  above  the  tuyeres,  and  made  the 
charges  of  iron  the  same,  or  three  hundred  weight. 

With  a  twenty-  two  inch  bed,  iron  came  down  in  twenty 
minutes  and  was  hot,  but  melted  slowly  throughout  the  heat. 

With  a  twenty-inch  bed,  iron  came  down  in  ten  minutes, 
melted  hot  and  faster  than  in  previous  heats. 

With  an  eighteen-inch  bed,  iron  came  down  in  five  minutes, 
and  melted  fast  and  hot  throughout  the  heat. 

With  a  sixteen-inch  bed,  iron  came  down  in  four  minutes, 
melted  hot  and  fast  at  first,  but  toward  the  latter  end  of  the 
charge  the  iron  was  a  little  dull,  and  as  each  charge  melted  the 
first  part  of  it  was  hot  and  the  latter  part  dull. 

With  a  fourteen-inch  bed,  iron  came  down  in  four  minutes. 
Melted  fast,  but  was  too  dull  for  light  work. 

With  a  twelve- inch  bed,  the  iron  was  very  dull,  and  with  a 
ten-inch  bed  it  was  so  dull  that  it  could  not  be  used  for  general 
foundry  work.  With  a  light  blast  and  low  melting  zone,  the 
iron  in  these  two  heats  would  probably  have  been  hot. 

In  these  experiments  we  obtained  the  best  general  results 
with  a  bed  of  eighteen  to  twenty  inches,  and  we  adopted  this 
bed  for  further  experiments. 

Our  next  experiments  were  to  learn  the  depth  of  the  melting 
zone  in  practical  melting,  and  the  amount  of  iron  that  should 
be  placed  in  each  charge  to  melt  iron  of  an  even  temperature 
throughout  a  heat.  In  these  experiments  we  made  the  charges 
of  fuel  placed  between  the  charges  of  iron  at  a  ratio  of  one 
pound  of  fuel  to  ten  pounds  of  iron. 


126  THE   CUPOLA   FURNACE. 

For  the  first  heat  we  put  in  a  bed  of  eighteen  inches,  on  this 
bed  four  cwt.  of  iron  on  this  iron  forty  pounds  of  coke,  on 
the  coke  four  cwt.  of  iron,  and  so  on  until  the  heat  was  all 
charged.  The  blast  was  the  same  as  before,  four  ounces  pres- 
sure with  two  large  tuyeres.  In  this  heat  the  iron  melted  hot 
and  fast,  and  of  an  even  temperature  throughout  the  heat. 

For  the  next  heat  we  made  the  charges  of  iron  five  cwt.,  and 
charges  of  coke  fifty  pounds.  The  results  in  melting  were 
practically  the  same  in  this  heat  as  in  the  former  one. 

For  the  next  heat  we  made  the  charges  of  iron  six  cwt.,  and 
coke  sixty  pounds.  In  this  heat  there  was  a  slight  change  in 
the  temperature  of  iron  as  the  last  of  each  charge  melted. 

For  the  next  heat  the  charges  were,  of  iron  seven  cwt.,  and 
coke  seventy  pounds.  The  iron  in  this  heat  was  a  little  dull 
when  the  last  of  each  charge  melted,  and  hot  when  the  first  of 
the  next  charge  melted,  making  the  iron  of  a  very  uneven  tem- 
perature throughout  the  heat.  How  often  have  we  seen  cupolas 
melt  in  this  way.  In  fact  it  is  a  common  thing  in  the  majority 
of  machine  and  jobbing  foundries  for  a  cupola  to  melt  iron  of 
an  uneven  temperature,  and  moulders  may  be  seen  almost 
every  heat  standing  round  the  cupola  watching  their  chance  to 
catch  a  ladle  of  hot  iron  to  pour  a  light  pulley  or  other  piece 
of  light  work.  The  uneven  melting  is  never  attributed  to  im- 
proper charging,  but  to  the  mysterious  working  of  the  cupola. 

For  the  next  heat  the  charges  were,  of  iron  eight  hundred 
weight,  and  coke  eighty  pounds.  In  this  heat  the  iron  was  hot 
until  the  last  of  the  first  charge,  when  it  became  dull.  The  first 
of  the  second  charge  was  hot,  but  it  soon  became  dull,  and 
before  the  charge  was  all  melted  it  was  very  dull.  At  the  be- 
ginning of  the  third  charge  the  iron  livened  up  a  little,  but  soon 
became  too  dull  to  pour  the  work  and  had  to  be  put  into  the 
pig  bed.  In  this  heat  we  used  exactly  the  same  percentage  of 
fuel  (one  to  ten)  between  the  charges  as  in  the  former  heats, 
which  should  have  raised  the  top  of  the  bed  to  its  former  height 
after  melting  a  charge  of  iron ;  but  it  did  not  do  so,  as  shown 
by  the  melting,  and  the  iron  became  duller  as  the  melting  of 


EXPERIMENTS   IN   MELTING.  127 

the  heat  progressed.  Had  another  charge  of  iron  been  put  in, 
it  probably  would  not  have  melted  at  all.  The  failure  of  the 
cupola  to  melt  well  in  the  latter  part  of  the  heat  was  not  due  to 
the  heat  being  too  large  for  the  cupola,  for  we  afterwards  melted 
heats  double  the  size  of  this  one  in  the  same  cupola,  and  had 
hot  iron  to  the  end  of  the  heat.  The  top  of  the  bed  was 
reduced  to  a  lower  level  in  this  heat  in  melting  the  heavier 
charges  of  iron,  and  the  fuel  in  the  bed  must  have  burned  away 
more  rapidly  when  the  bed  was  low,  or  the  charges  of  fuel  would 
have  restored  it  to  its  former  height,  as  with  the  light  charges 
of  iron.  We  tried  to  determine  this  point  more  accurately  by 
placing  a  vertical  slot  in  the  cupola  at  the  melting  zone  in  order 
to  observe  the  settling  of  the  charges,  but  the  heat  was  so  in- 
tense at  this  point  that  the  heat  could  not  be  confined  within 
the  cupola,  and  the  slot  had  to  be  closed  up. 

In  these  experiments  the  most  even  melting  was  done  with 
four  and  five  hundred  weight  charges.  With  these  charges  the 
fuel  kept  the  top  of  the  bed  at  a  proper  height  in  the  melting 
zone,  while  with  heavier  charges  it  became  lower  after  the  melt- 
ing of  each  charge,  until  it  became  too  low  to  make  hot  iron, 
and  if  the  charges  had  been  continued,  too  low  to  melt  at  all. 
We  afterward  tried  a  number  of  heats  with  a  twenty-inch  bed  and 
six  hundred-weight  charges,  and  did  good  melting.  With  a 
twenty-four  inch  bed  and  six  hundred-weight  charge  the  melt- 
ing was  even,  but  slow. 

By  the  experiments  in  this  cupola  it  was  found  that  it  was 
necessary  to  pass  the  blast  through  a  certain  amount  of  heated 
fuel  before  a  melting  zone  was  formed  in  a  cupola,  and  that  the 
amount  of  heated  fuel  required  for  the  blast  to  pass  through 
depended  upon  the  volume  of  the  latter.  This  heated  fuel  must 
be  above  the  tuyeres,  for  the  blast  passes  upward  from  the  tuy- 
eres, and  the  melting  zone  is  located  at  a  point  dependent  upon 
the  amount  of  heated  fuel  the  blast  must  pass  through  before  it 
becomes  heated  and  forms  the  zone.  The  blast  does  not  pass 
downward  from  the  tuyeres  except  when  it  may  be  permitted 
to  escape  from  the  tap  or  slag  hole,  and  fuel  placed  below  the 


128  THE   CUPOLA    FURNACE. 

tuyeres  takes  no  part  in  the  melting  of  iron  in  a  cupola.  When 
the  tuyeres  are  placed  high,  the  fuel  grows  deader  as  the 
heat  progresses  and  becomes  a  dull  cherry  red.  We  believe 
the  fire  would  go  out  in  this  part  of  a  cupola  in  a  long  heat 
were  it  not  for  the  molten  iron  dropping  through  the  fuel,  and 
the  occasional  escape  of  blast  from  the  tap  and  slag  holes. 

Iron  melted  high  in  a  cupola  is  made  dull  bypassing  through 
a  large  amount  of  fuel  below  the  tuyeres.  With  the  tuyeres  in 
this  cupola  placed  three  feet  above  the  bottom  and  iron  prop- 
erly charged  to  make  hot  iron,  it  was  found  impossible  to  get 
hot  iron  at  the  tap  hole  for  light  work.  This  was  undoubtedly 
due  to  the  iron  being  chilled  in  its  descent  through  the  fuel  under 
the  tuyeres,  for  the  same  charging  and  blast  produced  hot  iron 
with  low  tuyeres.  The  amount  of  fuel  under  the  tuyeres  makes 
no  difference  in  the  location  of  the  zone,  and  it  is  the  same 
distance  above  the  tuyeres  with  high  tuyeres  as  with  low  ones, 
when  the  blast  is  the  same.  No  iron  is  melted  outside  of  the 
zone,  and  fuel  placed  above  the  zone  takes  no  part  in  melting 
until  it  descends  into  the  zone.  If  too  large  a  quantity  of  fuel 
is  placed  in  a  bed,  the  iron  charged  upon  the  bed  is  placed  above 
the  zone  and  cannot  be  melted  until  fuel  in  the  zone  is  burned 
away  and  the  iron  settles  into  the  zone,  and  iron  is  a  long  time 
in  melting  after  the  blast  is  put  on.  If  too  great  a  quantity  of 
fuel  is  placed  in  the  charges,  the  top  of  the  bed  is  raised  above 
the  zone  after  the  melting  of  each  charge  of  iron,  and  fuel  must 
again  be  burned  away  before  the  iron  can  settle  into  the  zone 
to  be  melted,  and  there  is  a  stoppage  in  melting  at  the  end  of 
each  charge  of  iron.  If  the  charge  of  iron  is  made  too  heavy, 
the  bed  is  lowered  to  so  great  an  extent  in  melting  the  charge 
that  the  top  of  the  bed  is  not  raised  to  the  top  of  the  zone  by 
the  charge  of  fuel ;  and  as  each  succeeding  charge  is  melted,  the 
bed  sinks  lower  until  it  gets  near  the  bottom  of  the  zone  and 
iron  melts  dull,  or  sinks  below  the  bottom  of  the  zone,  and  melt- 
ing ceases.  Scarcely  any  two  cupolas  have  the  same  tuyere 
area  or  receive  the  same  volume  of  blast,  and  for  this  reason 
scarcely  any  two  cupolas  can  be  charged  exactly  alike.  To  do 


EXPERIMENTS   IN   MELTING.  1 29 

good  melting  in  a  cupola  it  is  necessary  for  the  melter  to  vary 
the  amount  of  fuel  in  the  bed  until  he  finds  the  top  of  the  melt- 
ing zone,  and  to  vary  the  charges  of  fuel  until  he  finds  the 
amount  of  fuel  that  will  raise  the  bed  to  the  top  of  the  zone 
after  melting  a  charge  of  iron.  He  must  vary  the  weight  of 
the  charges  of  iron  until  he  finds  the  amount  of  iron  that  can 
be  melted  in  a  charge  without  reducing  the  bed  too  low  to  be 
properly  restored  by  a  charge  of  fuel. 

After  twenty  years'  active  experience  in  melting  in  different 
cupolas,  the  above  are  the  only  practical  instructious  we  can 
give  for  charging  and  managing  a  cupola;  and  no  table  of 
charges  for  cupolas  of  different  sizes,  with  different  tuyere-area 
and  volume  of  blast,  would  be  of  any  practical  value  to  a  melter. 
Fuel  placed  in  a  cupola  above  the  zone  to  replenish  the  bed  is 
heated  by  the  escaping  heat  from  the  zone,  and  prepared  for 
combustion  in  the  latter,  and  iron  placed  above  the  zone  to  be 
melted  is  heated  and  prepared  for  melting  in  it,  and  the  more 
fuel  and  iron  brought  into  a  cupola  at  one  time  the  greater 
the  amount  of  heat  utilized.  And  the  charging  door  in  a 
cupola  should  be  placed  at  a  sufficient  height  to  admit  of  a 
large  amount  of  stock,  or  the  entire  heat,  being  put  into  the 
cupola  before  the  blast  is  put  on. 

The  melting  zone  is  developed  above  the  tuyeres  by  permit- 
ting the  blast  or  carbonic  oxide  to  escape  upward  after  passing 
through  the  zone,  and  it  may  be  developed  below  the  tuyeres 
by  permitting  it  to  escape  downward.  A  cupola  has  been  con- 
structed with  the  tuyeres  placed  near  the  top,  and  provision 
made  for  the  escape  of  the  blast  through  flues  arranged  near 
the  bottom  of  the  cupola.  It  was  hoped  by  this  plan  that  all. 
the  heat  produced  by  the  fuel  would  be  utilized  in  melting, 
and  the  entire  heat  placed  in  a  cupola  melted  very  quickly  and 
economically.  But  these  hopes  were  not  realized,  for  the  depth 
of  the  melting  zone  was  not  increased  by  being  below  the  tuy- 
eres, but  remained  the  same  as  above  the  tuyeres.  Iron  could 
not  be  melted  outside  of  the  zone,  and  the  cupola  was  a  failure. 
9 


I3O  THE   CUPOLA   FURNACE. 

MELTING   WITH    COAL. 

All  the  experiments  just  described  were  made  with  Connels- 
ville  coke,  but  we  also  made  a  number  of  similar  ones  in  this 
same  cupola  with  anthracite  coal.  In  these  experiments  it  was 
found  that  the  melting  zone  was  not  so  high  above  the  tuyeres 
with  the  same  volume  of  blast  as  with  coke,  nor  was  the  depth 
of  the  zone  so  great,  but  the  coal  did  not  burn  away  so  rapidly 
in  the  zone  as  coke  and  heavier  charges  of  iron  could  be 
melted.  In  these  experiments  the  best  results  were  obtained 
with  a  bed  of  about  fourteen  inches  above  the  tuyeres  and 
charges  of  coal  of  one  to  eight,  and  charges  of  iron  from  one- 
half  to  two-thirds  heavier  than  with  coke.  An  opinion  prevails 
among  foundrymen  that  the  tuyeres  in  a  cupola  must  be  espe- 
cially adapted  for  coke,  or  coke  cannot  be  used.  In  these 
experiments  we  used  the  same  tuyeres  as  with  coke,  placed 
them  at  the  same  heights,  and  found  no  difficulty  in  melting 
with  them ;  and  iron  may  be  melted  in  almost  any  cupola  with 
either  coal  or  coke,  if  charged  to  suit  the  fuel  and  tuyeres. 

SOFTENING   HARD    IRON. 

In  experimenting  with  iron  in  a  crucible,  we  found  that  the 
hardest  iron  could  be  softened  by  melting  it,  or  subjecting  it 
to  a  prolonged  heat  in  a  closed  crucible  with  charcoal.  We 
•thought  the  same  results  might  be  obtained  in  a  cupola  by  pass- 
ing molten  iron  through  charcoal  in  its  descent  from  the  melting 
zone  to  the  bottom  of  the  cupola.  It  had  been  found  that  fuel 
below  the  tuyeres  was  not  consumed  during  a  heat,  and  we  de- 
cided to  try  permitting  the  iron  after  melting  to  drop  through  a 
bed  of  charcoal  under  the  tuyeres.  The  tuyeres  were  placed 
twenty- four  inches  above  the  bottom  and  the  cupola  was  filled 
with  charcoal  to  the  tuyeres,  and  above  the  tuyeres  coke  to  do 
.the  melting  was  placed.  We  were  afraid  the  charcoal  would  all 
•be  burned  up  before  the  coke  above  the  tuyeres  was  ready  for 
•  charging,  and  to  prevent  this  we  put  in  a  wood  fire  to  dry  the 
bottom  and  warm  the  cupola.  When  this  was  burned  out  we 
filled  the  cupola  with  charcoal  to  the  tuyeres,  put  in  shavings 


EXPERIMENTS    IN   MELTING.  131 

and  wood,  and  lit  the  fire  at  the  tuyeres  above  the  charcoal. 
The  charcoal  was  only  burned  a  little  on  top  when  the  coke  was 
ready  for  charging,  and  not  on  fire  at  all  in  the  bottom  of  the 
cupola.  When  the  cupola  was  ready  for  charging  we  put  in 
one  charge  of  five  cwt.  of  hard  pig  and  scrap,  and  put  on  the 
blast.  The  iron  melted  hot,  but  in  its  descent  through  the 
charcoal  to  the  bottom  of  the  cupola  was  cooled  to  such  an 
extent  that  it  would  scarcely  run  from  the  tap  hole,  and  the 
heat  was  a  failure.  This  was  not  the  only  failure  in  our  exper- 
imental melting,  and  we  are  afraid  if  we  attempted  to  write  up 
all  our  experimental  heats  more  failures  than  successes  would 
be  recorded.  Experiments  in  a  cupola  are  not  always  a  suc- 
cess, no  matter  how  much  care  may  be  taken  in  making  them. 
Experimenters  generally  report  only  their  successful  experi- 
ments, but  if  they  would  report  their  failures  also,  they  would 
give  much  valuable  information  and  save  other  experimenters 
much  time  and  expense  in  going  over  the  same  ground. 

For  the  next  heat  we  placed  shavings  over  the  bottom,  filled 
the  cupola  with  charcoal  to  the  tuyeres,  and  put  shavings  and 
wood  on  top  of  the  charcoal  for  lighting  the  coke.  There  was 
a  great  deal  of  trouble  in  getting  the  two  fires  to  burn  at  the 
same  time,  and  the  results  were  not  at  all  satisfactory. 

For  the.  next  heat  we  filled  the  cupola  with  charcoal  to  a  short 
distance  above  the  tuyeres  to  allow  for  burning  away,  and 
settling,  and  lit  the  fire  from  the  front  in  the  ordinary  way,  and 
as  soon  as  it  was  burned  up  to  the  tuyeres  put  in  the  front  to 
shut  off  the  draught  at  the  bottom.  This  worked  very  well,  and 
we  found  we  had  a  good  bed  of  hot  charcoal  up  to  the  tuyeres 
when  the  cupola  was  ready  for  charging.  On  the  bed  of  coke 
was  placed  a  charge  of  five  cwt.  of  pig  and  scrap,  all  white  hard, 
and  the  blast  put  on.  The  charcoal  bed  did  not  appear  to 
burn  away  at  all  during  the  heat,  and  the  iron  melted  well  and 
came  down  hot.  When  tapped  almost  as  fast  as  melted,  the 
iron  was  very  little  softened  by  the  charcoal.  But  when  allowed 
to  remain  in  the  cupola  for  some  time  after  melting,  it  was 
softened  to  the  extent  of  becoming  a  mottled  iron  when  run  into 


132  THE   CUPOLA   FURNACE. 

pigs  or  heavy  work.  But  when  held  in  the  cupola  for  a  suffi- 
cient length  of  time  to  soften  it  to  this  extent,  the  iron  became 
very  dull  and  not  fit  to  run  light  work.  This  experiment  was 
repeated  a  number  of  times  with  different  grades  of  hard  iron, 
but  we  never  found  any  marked  change  in  the  iron  when  tapped 
almost  as  fast  as  melted  and  hot.  When  held  in  the  cupola  a 
sufficient  length  of  time  to  soften  it  to  a  limited  extent,  it  was 
too  dull  to  run  light  work,  for  the  flowing  properties  of  the  iron 
were  not  to  any  extent  increased  by  the  charcoal.  As  there  is 
no  difficulty  in  making  mixtures  of  iron  soft  enough  for  heavy 
work  into  which  dull  iron  can  be  poured,  we  could  see  no  ad- 
vantage in  using  charcoal  in  this  way. 

TIME    FOR    CHARGING. 

There  is  a  wide  difference  of  opinion  among  foundrymen  as 
to  the  proper  time  for  charging  iron  on  the  bed  and  putting  on 
the  blast  after  charging.  Some  claim  that  if  iron  is  charged 
several  hours  before  the  blast  is  put  on,  fuel  in  the  bed  is 
burned  up  and  the  heat  is  wasted,  and  others  claim  that  heat 
is  wasted  by  putting  on  the  blast  as  soon  as  iron  is  charged. 
In  some  foundries  the  cupola  is  filled  with  fuel  and  iron  to  the 
charging  door  before  lighting  the  fire.  In  others,  iron  is 
charged  after  the  fire  is  burned  up  and  permitted  to  remain  in 
the  cupola  two  or  three  hours  before  the  blast  is  put  on,  and  in 
some  foundries  the  blast  is  put  on  as  soon  as  charging  of  iron 
begins. 

We  made  a  number  of  experiments  in  the  heats  just  described 
to  ascertain  the  proper  time  for  charging  and  putting  on  the 
blast  after  charging.  Iron  charged  before  the  fire  was  lit  was 
very  uncertain  as  to  the  time  at  which  it  melted  after  the  blast 
was  put  on.  In  some  heats  it  melted  in  five  minutes  and  in 
others  in  thirty  minutes. 

Iron  charged  before  the  fire  was  burned  through  the  bed  was 
a  long  time  in  melting  after  the  blast  was  put  on,  and  the  time 
of  melting  was  very  uncertain ;  in  some  heats  it  melted  in  ten 
minutes,  and  in  others  not  for  thirty  minutes.  Iron  charged 


EXPERIMENTS    IN   MELTING.  133 

after  the  bed  was  burned  through  and  the  heavy  smoke  burned 
off,  melted  sooner  after  the  blast  was  on  and  was  more  regular 
in  time  of  melting,  and  generally  melted  in  ten  minutes  when 
the  bed  was  of  a  proper  height. 

Iron  charged  two  or  three  hours  before  the  blast  was  put  on, 
melted  in  from  three  to  five  minutes  after  it  was  put  on. 

Iron  charged  and  the  blast  put  on  as  soon  as  charging  began, 
melted  in  from  fifteen  to  twenty  minutes. 

In  these  heats  it  was  found  that  time  and  power  to  run  the 
blower  were  saved  by  charging  the  iron  two  or  three  hours 
before  putting  on  the  blast,  for  iron  melted  in  from  three  to  five 
minutes  after  the  blast  was  on,  and  melted  equally  as  fast  during 
the  heat  as  when  the  blast  was  put  on  soon  after  the  iron  was 
charged.  We  do  not  think  that  any  fuel  was  wasted  by  this 
manner  of  charging,  for  we  shut  off  the  draught  from  the  bottom 
of  the  cupola  by  putting  in  the  front  and  closing  all  the  tuyeres 
but  one  as  soon  as  the  bed  was  ready  for  charging.  The  bed 
burned  very  little  after  the  front  was  put  in,  and  the  heat  that 
arose  from  it  was  utilized  in  heating  the  first  charge  of  iron 
preparatory  to  melting,  or  iron  would  not  have  melted  in  less 
time  than  when  the  blast  was  put  on  as  soon  as  the  iron  was 
charged.  There  is  great  risk  in  charging  iron  before  the  fire  is 
lit  or  has  burned  up,  for  the  fire  may  go  out  or  not  burn  up 
evenly,  and  we  prefer  to  have  the  bed  burned  through  before 
charging  the  iron. 

DEVICES    FOR    RAISING   THE    BOTTOM    DOORS. 

A  number  of  devices  have  been  used  for  raising  the  bottom 
doors  of  cupolas  into  place,  and  thus  avoiding  the  trouble  and 
labor  of  raising  them  by  hand.  One  of  the  oldest  of  these  de- 
vices is  a  long  bar,  one  end  of  which  is  bolted  to  the  under  side 
of  the  door,  on  the  other  end  is  cast  a  weight  or  ball  almost 
sufficient  to  balance  the  door  upon  its  hinges  when  raised. 
When  the  door  is  down  the  bar  stands  up  alongside  of  the 
cupola,  and  when  it  is  desired  to  raise  the  door  the  bar  and 
weight  are  swung  downward.  As  the  weight  descends  the 


134  THE   CUPOLA   FURNACE. 

door  is  balanced  upon  its  hinges  and  swings  up  into  place, 
where  it  is  supported  by  a  prop  or  other  support.  This  device, 
when  properly  arranged  and  in  good  order,  raises  the  door 
very  easily  and  quickly  into  place,  but  it  is  continually  getting 
out  of  order.  The  sudden  dropping  of  the  door  in  dumping 
and  the  consequent  sudden  upward  jerk  given  to  the  heavy 
weight  on  the  end  of  the  bar,  frequently  breaks  the  bar  near 
the  end  attached  to  the  door  or  breaks  the  bolts  by  which  the 
bar  is  attached  to  the  door,  and  the  door  is  sometimes  broken 
by  the  bar.  For  these  reasons  this  device  is  very  little  used. 

Another  device,  and  probably  the  best  one  for  raising  heavy 
doors,  is  to  cast  large  lugs  with  a  large  hole  in  them,  on  the 
bottom  and  the  door,  and  put  in  an  inch  and  a  half  shaft 
of  a  sufficient  length  to  have  one  end  extend  out  a  few  inches 
beyond  the  edge  of  the  bottom  plate.  The  door  is  keyed 
fast  upon  the  shaft,  and  the  shaft  turns  in  the  lugs  upon  the 
bottom  when  the  door  is  raised  or  dropped.  An  arm  or  crank 
is  placed  upon  the  end  of  the  shaft,  pointing  in  the  same 
direction  from  the  shaft  as  the  door.  When  the  door  is  down 
the  arm  hangs  down  alongside  of  the  iron  post  or  column 
supporting  the  cupola  and  is  out  of  the  way  in  removing  the 
dump,  and  when  the  door  is  up  the  arm  is  up  alongside  of  the 
bottom  plate,  out  of  the  way  of  putting  in  the  bottom  props. 
The  door  is  raised  by  a  pair  of  endless  chain  pulley  blocks  at- 
tached to  the  under  side  of  the  scaffold  floor  at  the  top  and  the 
end  of  the  arm  at  the  bottom,  and  it  is  only  necessary  to  draw 
up  the  arm  with  the  chain  to  raise  the  door  into  place.  This 
is  one  of  the  best  devices  we  have  seen  for  raising  heavy  doors. 

Another  one,  equally  good  for  small  doors  and  less  expensive, 
is  to  make  the  end  of  the  shaft  square  and  raise  the  door  by 
hand  with  a  bar  or  wrench  five  or  six  feet  long,  placed  upon 
the  end  of  the  shaft.  The  bar  is  placed  upon  the  shaft  in  an 
'upright  position,  and  by  drawing  down  the  end  of  the  bar  the 
door  is  swung  up  into  place  by  the  rotation  of  the  shaft  on  to 
which  it  is  keyed.  When  the  door  is  in  place  the  bar  is  re- 
moved from  the  end  of  the  shaft,  and  is  not  at  all  in  the  way  of 
handling  the  iron  or  managing  the  cupola. 


CHAPTER  VI. 

FLUXING   OF   IRON   IN   CUPOLAS. 

FLUX  is  the  term  applied  to  a  substance  which  imparts 
igneous  fluidity  to  metals  when  in  a  molten  state,  and  has  the 
power  to  separate  metals  contained  in  metallic  ores  from  the 
non-metallic  substances  with  which  they  are  found  in  com- 
bination ;  also  to  separate  from  metals  when  in  a  fluid  state  any 
impurities  they  may  contain.  Fluxes  are  also  used  for  the  pur- 
pose of  making  a  fluid  slag  in  furnaces  to  absorb  the  non- 
metallic  residue  from  metals  or  ores  and  ash  of  the  fuel,  and 
removing  them  from  the  furnace  to  prevent  clogging  and  to 
keep  the  furnace  in  good  working  order  for  a  greater  length  of 
time.  The  materials  used  as  fluxes  for  the  various  metals  are 
numerous  and  varied  in  nature  and  composition,  but  we  shall 
only  consider  those  employed  in  the  production  of  iron  and  the 
melting  of  iron  for  foundry  work. 

The  substances  employed  for  this  purpose  are  numerous,  but 
they  consist  chiefly  of  the  carbonate  of  lime  in  its  various 
forms,  the  principal  one  of  which  is  limestone. 

In  the  production  of  pig  iron  from  iron  ore  in  the  blast  fur- 
nace, limestone  is  used  for  the  two-fold  purpose  of  separating 
the  iron_fmjiLJlie__ore,  and  for  liquefying  anot  absorbing  the 
non-metallic  residuum  of  the  ore  and  ash  of  the  fuel,  and  carry- 
ing them  out  of  the  furnace.  For  this  purpose  large  quantities 
of  limestone  are  put  into  the  furnace  with  the  fuel  and  ore.  The 
stone  melts  and  produces  a  fluid  slag,  which  absorbs  the  non- 
metallic  residuum  of  the  ore  and  ash  of  the  fuel  in  its  descent 
to  the  bottom  of  the  furnace.  Thence  it  is  drawn  out  at  the 
slag  hole,  and  carries  with  it  all  those  non-metallic  substances 
which  tend  to  clog  and  choke  up  the  furnace.  By  this  process 


136  THE   CUPOLA   FURNACE. 

of  fluxing  the  furnace  is  kept  in  good  smelting  order  for  months, 
and  even  years.  Were  it  not  for  the  free  use  of  limestone,  the 
furnace  would  clog  up  in  a  few  days. 

The  blast  furnace  is  a  cupola  furnace,  and  is  constructed  upon 
the  same  general  principle  as  the  foundry  cupola.  Foundry- 
men  long  ago  conceived  the  idea  of  using  limestone  as  a  cupola 
flux.  In  many  foundries  it  is  the  practice  to  use  a  few  shovelfuls 
or  a  few  riddlefuls  of  finely  broken  limestone  in  the  cupola  on  the 
last  charge  of  iron,  or  distributed  through  the  heat,  a  few  hand- 
fuls  to  each  charge  of  iron.  The  object  in  using  limestone  in 
this  way  is  not  to  produce  a  slag  to  be  drawn  from  the  cupola, 
but  to  make  a  clean  dump  and  a  brittle  slag  or  cjnder  in  the 
cupola,  that  can  be  easily  broken  down  and  chipped  from  the 
lining  when  making  up  the  cupola  for  a  heat. 

Limestone  used  in  this  way  does  not  produce  a  sufficient 
quantity  of  slag  to  absorb  the  dirt  from  the  iron  and  ash  of  the 
fuel  and  keep  the  cupola  open  and  working  free,  but  rather 
tends  to  cause  bridging  and  reduce  the  melting  capacity  of  the 
cupola. 

The  making  of  a  brittle  cinder  in  a  cupola  by  the  use  of  lime- 
stone depends  to  a  great  extent  upon  the  quality  of  the  stone. 
Some  limestones  have  a  great  affinity  for  iron  and  combine  with 
it  freely  when  in  a  molten  state,  while  others  have  but  little 
affinity  for  iron  and  do  not  enter  into  combination  with  it  at  all. 
In  the  cinder  piles  about  blast  furnaces  we  find  cinder  almost 
as  heavy  and  hard  to  break  as  iron,  resisting  the  action  of  the 
atmosphere  for  years ;  while  at  others  we  find  a  brittle  cinder 
that  crumbles  to  pieces  after  a  short  exposure  to  the  atmo- 
sphere, or  even  slacks  down  like  quicklime  when  wet  with  water. 
In  a  cupola  we  may  have  a  hard  or  brittle  cinder  produced  by 
limestone.  The  results  obtained  from  the  use  of  limestone  in 
small  quantities  in  a  cupola  are  so  uncertain  that  we  do  not  think 
they  justify  the  foundryman  in  using  it. 

LIMESTONE    IN    LARGE   QUANTITIES. 

The  tendency  of  slag  or  cinder  in  a  cupola  is  to  chill  and 


FLUXING   OF   IRON   IN   CUPOLAS.  137 

adhere  to  the  lining  just  over  the  tuyeres  and  around  the  cupola 
at  this  point,  and  prevent  the  proper  working  of  the  furnace. 
So  great  is  this  tendency  to  bridge  that  a  small  cupola  will  not 
melt  properly  for  more  than  two  hours,  and  a  large  one  for  more 
than  three  hours.  To  overcome  this  tendency  to  clog  and 
bridge,  foundrymen  in  many  cases  have  adopted  the  blast- 
furnace plan  of  using  a  large  per  cent,  of  limestone  as  a  flux  in 
their  cupolas,  and  tapping  slag. 

When  a  large  per  cent,  of  limestone  is  charged  with  the  iron 
in  a  cupola,  it  melts  when  it  settles  to  the  melting  point  and 
forms  a  fluid  slag.  This  slag  settles  through  the  stock  to  the 
bottom,  and  in  its  descent  melts  and  absorbs  the  ash  of  the  fuel 
and  dirt  or  sand  from  the  iron  and  carries  them  to  the  bottom 
of  the  cupola,  where  the  slag  and  dirt  it  contains  may  be  drawn 
off  and  the  cupola  kept  in  good  melting  order  and  in  blast  for 
days  at  a  time.  The  amount  of  limestone  required  per  ton  of 
iron  to  produce  a  fluid  slag  depends  upon  the  quality  of  the 
stone  and  the  condition  of  the  iron  to  be  melted.  It  is  the 
custom  in  some  foundries,  where  the  sprews  and  gates  amount 
to  from  thirty  to  forty  per  cent,  of  the  heat,  to  melt  them  with- 
out milling  to  remove  the  sand,  and  to  use  enough  limestone  in 
the  cupola  to  produce  a  sufficient  quantity  of  slag  to  absorb 
and  carry  out  of  the  cupola  the  sand  adhering  to  them.  In 
this  case  a  larger  per  cent,  of  limestone  is  required  than  would 
be  necessary  if  the  sprews  and  gates  were  milled  and  only  clean 
iron  melted.  Poor  fuel  also  requires  a  greater  amount  of  slag 
to  absorb  the  ash  than  good  fuel,  and  a  lean  limestone  must  be 
used  in  larger  quantities  than  a  stone  rich  in  lime.  The  quan- 
tity required  to  produce  a  fluid  slag,  therefore,  varies  with  the 
quality  of  the  limestone  and  the  conditions  under  which  it  is 
used,  and  amounts  to  from  25  to  100  pounds  per  ton  of  iron 
melted. 

The  weight  of  the  slag  drawn  from  a  cupola  when  the  sprew? 
and  gates  are  not  milled,  and  the  cupola  is  kept  in  blast  for  a 
number  of  hours,  is  about  one-third  greater  than  the  weight  of 
the  limestone  used.  When  the  sprews  and  gates  are  milled, 


138  THE   CUPOLA   FURNACE. 

the  weight  of  the  slag  is  about  equal  to  the  weight  of  the  lime- 
stone. When  the  cupola  is  only  run  for  a  short  time  and  slag 
only  drawn  during  the  latter  part  of  the  heat,  the  weight  of  the 
slag  is  less  than  the  weight  of  the  limestone. 

The  slag  drawn  from  a  cupola  has  been  found,  by  chemical 
analysis,  to  contain  from  4  to  7  per  cent,  of  combined  iron  and 
numerous  small  particles  of  shot  iron  mechanically  locked  up 
in  the  slag.  These  cannot  be  recovered  except  at  a  greater 
cost  than  the  value  of  the  metal.  In  a  number  of  tests  made 
in  the  same  cupola,  we  found  the  loss  of  iron  to  be  from  3  to  4 
per  cent,  greater  when  the  cupola  was  slagged. 

EFFECT    OF    FLUX   UPON    IRON. 

Many  of  the  limestones  and  other  mineral  substances  em- 
ployed as  cupola  fluxes  contain  more  or  less  finely  divided 
oxides,  silicates,  etc.,  in  combination  with  earthy  materials, 
The  flux  is  often  reduced  in  a  cupola  and  its  component  parts 
separated,  and  in  minute  quantities  they  alloy  with  the  iron  and 
injure  its  quality.  The  conjoined  effect  upon  iron  of  these 
diffused  oxides,  silicates,  etc.,  liberated  in  a  cupola  from  their 
native  elements  in  fluxes,  is  to  prevent  the  metal  running  clean 
in  the  mould  or  making  sharp,  sound  castings,  and  the  tensile 
and  tranverse  strengths  are  frequently  impaired  by  them.  When 
the  oxides,  silicates,  etc.,  are  not  separated  in  the  cupola  from 
their  native  elements,  they  do  not  impair  the  quality  of  the 
metal,  nor  do  they  improve  it.  The  tendency  of  the  cupola 
furnace  is  to  clog  and  bridge  over  the  tuyeres,  and  concentrate 
the  blast  upon  the  iron  through  a  small  opening  in  the  center 
and  injure  its  quality.  If  by  the  free  use  of  limestone  we  pre- 
vent bridging  and  keep  the  furnace  working  open  and  free,  we 
avoid  injuring  the  iron  in  melting  by  the  .concentration  of  a 
strong  blast  upon  it.  The  effect,  therefore,  of  limestone  in  a 
cupola  is  not  to  improve  the  quality  of  iron,  but  to  prevent  its 
deterioration  in  melting. 


FLUXING   OF  IRON   IN   CUPOLAS.  139 

THE   ACTION   OF    FLUXES    ON    LINING. 

Limestone  and  other  minerals  employed  as  fluxes  frequently 
contain  impurities  which  enter  into  combination  with  the  lining 
material  of  a  furnace  and  render  it  fusible.  This  was  illustrated 
at  the  foundry  of  John  D.  Johnson  &  Co.,  Hainesport,  N.  J.,  in 
1893.  The  cupola  front  had  been  put  in  with  new  moulding 
sand  for  a  long  time,  and  no  flux  used  in  the  cupola.  The  sand 
made  an  excellent  front  that  resisted  the  action  of  the  heat  and 
molten  iron  upon  it.  As  the  heats  enlarged,  it  became  neces- 
sary to  use  flux  and  tap  slag  to  run  off  the  heat.  Oyster  shells 
were  used  and  produced  a  slag  that  flowed  freely  and  had  no 
effect  upon  the  sand  in  the  front.  When  the  supply  of  shells 
became  exhausted,  a  limestone  was  used  in  place  of  them. 
Trouble  then  began  with  the  front.  It  was  melted  by  the  flux 
into  a  thick,  tough  slag  that  settled  down  and  closed  up  the  tap 
hole,  and  iron  could  only  be  drawn  by  cutting  away  a  large 
portion  of  the  front  to  enlarge  the  tap  hole.  Mr-.  Johnson 
called  at  our  office  to  learn  what  could  be  done  to  keep  the  tap 
hok -open.  We  advised  that  the  front  material  be  changed  and 
a  mixture  of  fire-clay  and  sharp  sand  be  used  in  place  of  mould- 
ing sand.  This  was  done,  and  there  was  no  further  trouble  in 
keeping  the  tap  hole  open  and  in  good  order  to  run  off  the 
heat.  This  serves  to  illustrate  the  effect  of  fluxes  upon  lining 
material.  With  no  flux  and  with  oyster  shells  the  moulding 
sand  resisted  the  heat  and  pressure  of  molten  iron  and  slag 
upon  the  front;  but  with  limestone  it  melted  into  a  thick, 
tough  slag.  This  was  due  to  some  property  in  the  limestone 
entering  into  combination  with  the  sand  and  making  it  fusible. 
Had  the  cupola  been  lined  with  this  moulding  sand,  the  entire 
lining  would  have  been  cut  out  in  one  heat,  while  it  would  have 
stood  many  heats  with  shells  or  no  flux  at  all. 

From  the  various  qualities  of  cupola  brick  and  lining  mate- 
rial now  in  the  market,  a  lining  may  be  selected  that  will  resist 
the  action   of  almost  any  flux  or  slag,  and  foundrymen   may 
select  a  flux  to  suit  the  lining  or  a  lining  to  suit  the  flux,  which 
ever  they  find  to  be  the  most  profitable  in  their  locality. 


140  THE   CUPOLA   FURNACE. 

HOW   TO   SLAG   A    CUPOLA. 

Foundrymen  sometimes  experience  trouble  in  slagging  their 
cupolas.  This  is  largely  due  to  a  lack  of  knowledge  in  charging 
the  limestone  and  drawing  the  slag,  for  any  cupola  can  be 
slagged  if  properly  worked.  To  draw  slag  from  a  cupola,  a  suffi- 
cient quantity  of  limestone  or  other  slag-producing  material 
must  be  charged  in  the  cupola  with  the  iron  to  make  a  fluid 
slag.  The  exact  amount  required  can  only  be  learned  by  ex- 
perimenting with  the  fluxing  material  used,  but  it  is  generally 
from  fifty  to  sixty  pounds  of  good  limestone  per  ton  of  iron, 
when  the  remelt  is  not  milled.  The  limestone  is  generally 
charged  on  top  of  the  iron  and  put  in  with  each  .charge  after 
the  melter  begins  using  it.  No  limestone  is  used  with  the  iron 
on  the  bed  or  first  few  charges  of  iron.  In  small  cupolas  lime- 
stone is  generally  charged  with  the  second  or  third  charge  of 
iron.  In  large  cupolas,  when  the  charges  of  iron  are  light,  six 
or  eight  charges,  or  generally  about  one-sixth  of  the  heat,  are 
charged  without  limestone.  This  is  the  way  limestone  is  used 
when  the  cupola  is  run  in  the  ordinary  way  for  a  few  hours. 
When  the  cupola  is  run  for  some  special  work,  the  limestone  is 
charged  in  a  number  of  different  ways. 

The  slag  is  drawn  from  the  cupola  through  an  opening  known 
as  the  slag-hole.  This  opening  is  made  through  the  casing  and 
lining  under  the  lower  level  of  the  tuyeres  and  at  a  point  in  the 
cupola  where  it  will  be  out  of  the  way  in  removing  iron  from 
the  spout  and  convenient  for  removing  the  slag.  The  height 
the  slag  hole  is  placed  above  the  sand  bottom  depends  upon 
how  the  iron  is  drawn  from  the  cupola.  When  it  is  desired  to 
hold  iron  in  a  cupola  until  a  sufficient  quantity  is  melted  to  fill 
a  large  ladle,  the  slag  hole  is  placed  high,  and  when  the  iron  is 
drawn  as  fast  as  melted  the  slag  hole  is  placed  low.  When  the 
slag  hole  is  placed  high,  slag  can  only  be  drawn  as  the  cupola 
fills  up  with  iron  and  raises  it  to  the  slag  hole.  When  the  iron 
is  withdrawn  from  the  cupola,  the  slag  falls  and  the  slag  hole  is 
closed  with  a  bod  to  prevent  the  escape  of  blast.  When  the 
iron  is  drawn  from  the  cupola  as  fast  as  melted,  the  slag  hole  is 


FLUXING   OF   IRON   IN   CUPOLAS.  141 

placed  low  and  when  opened  it  is  permitted  to  remain  open 
through  the  remainder  of  the  heat.  This  is  the  best  way  of 
drawing  slag  from  a  cnpola,  for  the  flow  is  regulated  by  the 
amount  of  slag  in  the  cupola,  and  if  the  hole  is  not  made  too 
large,  there  is  no  escape  of  blast. 

The  slag  in  the  bottom  of  a  cupola  takes  up  impurities  from 
the  fuel  and  iron,  and  if  permitted  to  remain  in  the  cupola  for 
too  long  a  time,  it  may  become  so  thick  and  mucky  it  will  not 
flow  from  the  slag  hole.  Or  it  may  be  filled  with  impurities, 
become  over-heated,  boil  up  and  fill  the  tuyeres  with  slag ;  and 
when  boiling,  it  will  not  flow  from  the  cupola  through  a  small 
slag  hole.  The  time  for  drawing  the  slag  from  a  cupola  is 
therefore  a  matter  of  great  importance.  The  slag  hole  is  gen- 
erally opened  in  from  half  an  hour  to  an  hour  after  the  cupola 
begins  to  melt,  and  when  placed  low  is  permitted  to  remain 
open  throughout  the  remainder  of  the  heat.  When  placed  so 
high  that  slag  can  only  be  drawn  when  the  cupola  fills  up  with 
molten  iron,  it  should  be  opened  as  soon  as  the  slag  begins  to 
rise  and  closed  as  soon  as  it  falls  below  the  opening. 

DOES   IT   PAY   TO    SLAG   A    CUPOLA  ? 

Nothing  is  gained  by  slagging  a  cupola  when  the  sprews  and 
gates  are  milled  and  the  heat  can  be  melted  successfully  in  the 
cupola  without  slagging ;  but  a  great  saving  in  labor  and  wear 
and  tear  of  machinery  can  be  effected  in  many  foundries  by 
melting  the  sprews  and  gates  with  the  sand  on,  and  slagging  to 
carry  the  sand  out  and  keep  the  cupola  working  free.  A 
cupola  can  not  be  made  to  melt  iron  faster  by  slagging,  but  it 
can  be  kept  in  blast  and  in  good  melting  condition  for  a  greater 
length  of  time  and  a  much  larger  amount  of  iron  melted  by 
slagging.  Foundrymen  who  find  their  cupolas  temporarily  too 
small  to  melt  the  quantity  of  iron  required  for  their  work,  can 
overcome  the  difficulty  by  slagging  the  cupola  and  keeping  it 
in  blast  for  a  greater  length  of  time. 

In  endeavoring  to  make  an  estimate  of  the  cost  of  slagging  a 
cupola,  we  found  that  the  cost  of  limestone  in  different  localities 


142  THE   CUPOLA   FURNACE. 

varied  from  50  cents  to  $3  per  ton.  The  amount  used  varied 
from  25  to  100  pounds  per  ton  of  iron  melted.  The  amount  of 
slag  drawn  varied  from  25  to  100  pounds  per  ton  of  iron.  The 
iron  combined  with  the  slag  varied  from  4  to  7  per  cent.  With 
these  wide  differences  in  the  cost  and  quantity  of  limestone 
used,  and  the  difference  in  the  quantity  of  slag  drawn  and  per 
cent,  of  iron  it  contained,  we  found  it  impossible  to  make  an 
estimate  that  would  be  of  any  practical  value  to  foundrymen. 
Such  an  estimate  must  be  made  at  each  foundry  to  be  of  any 
practical  value. 

SHELLS. 

Oyster,  clam  and  other  shells  are  largely  composed  of  lime, 
and  are  frequently  used  as  a  flux  in  place  uf  limestone  in  locali- 
ties where  they  can  be  procured  at  a  less  cost  than  limestone. 
The  shells  are  charged  in  the  same  way  as  limestone  and  in 
about  the  same  proportion  to  the  iron.  They  may  be  used  in 
place  of  limestone  either  in  large  or  small  quantities,  and  have 
about  the  same  effect  upon  the  iron  and  cupola  as  limestone. 
When  used  in  large  quantities,  they  produce  a  fluid  slag  that 
keeps  the  cupola  working  free  and  flows  freely  from  the  slag 
hole,  carrying  with  it  the  refuse  of  melting  that  clogs  the  cupola. 
When  the  heat  first  strikes  shells  in  a  cupola,  they  produce  a 
crackling  noise  and  flakes  of  shell  may  be  seen  to  pass  up  the 
stack,  and  the  foundry  roof,  when  flat,  is  often  covered  with 
flakes  of  shell  after  a  heat,  when  shells  are  used  in  large  quanti- 
ties. The  crackling  is  due  to  the  destruction  of  the  hard  inner 
surface  of  the  shell ;  the  flakes  thrown  from  the  cupola  are  en- 
tirely of  this  surface,  and  the  loss  of  shell  is  not  as  great  as  it 
would  appear  to  be  at  first  sight.  The  remainder  of  the  shell 
melts  and  forms  a  fluid  slag  that  absorbs  the  refuse  of  melting, 
becomes  thick  and  helps  to  clog  up  a  cupola  when  the  shells 
are  used  in  small  quantities,  or  assists  in  keeping  it  open  when 
used  in  large  quantities. 

MARBLE    SPALLS. 

Marble  is  another  of  the  carbonates  of  lime,  and  the  spalls  or 


FLUXING   OF   IRON   IN   CUPOLAS.  143 

chippings  from  marble  quarries  or  works  are  quite  extensively 
used  in  some  localities  as  a  cupola  flux.  Their  action  in  a 
cupola  and  their  effect  upon  iron  is  very  similar  to  that  of  lime- 
stone, and  they  are  used  in  the  same  way  and  in  about  the 
same  proportions.  There  are  a  number  of  other  substances, 
such  as  fluor-spar,  feld-spar,  quartz-rock  and  a  number  of 
chemical  compounds  that  are  used  as  cupola  fluxes. 

In  1873,  when  engaged  in  the  manufacture  of  malleable  iron, 
we  began  experimenting  with  mineral  and  chemical  materials 
with  the  view  of  making  a  cheap  malleable  iron,  and  changing 
the  nature  of  iron  in  a  cupola  furnace  so  that  it  might  be  an- 
nealed at  a  less  cost,  and  produce  stronger  iron.  In  this  we 
succeeded  to  some  extent,  and  then  drifted  off  into  improving 
the  quality  of  iron  in  a  cupola  for  grey  iron  castings ;  this  we 
have  followed  for  nearly  twenty  years.  During  this  time  we  have 
melted  iron  in  foundries  all  over  the  greater  part  of  the  United 
States  and  Canada,  and  have  constructed  and  worked  a  number 
of  experimental  cupolas  of  our  own,  to  learn  the  effect  of  dif- 
ferent mineral  and  chemical  substances  upon  iron  and  cupola 
linings.  In  these  investigations  we  have  used  all  the  mineral  and 
chemical  fluxes  known  to  metallurgical  science,  and  observed 
their  effect  upon  the  various  grades  of  iron  employed  for 
foundry  work. 

In  these  experiments  it  was  found  that  iron  can  be  improved 
or  injured  when  melted  in  a  cupola  furnace,  and  is  often  ruined 
as  a  foundry  iron  by  improper  melting  and  fluxing.  The  point 
at  which  iron  is  melted  in  a  cupola  has  a  great  deal  to  do  with 
its  quality.  Iron  melted  too  high  in  a  cupola  is  burned  and 
hardened ;  melted  too  low,  it  runs  dirty  in  a  mould  ;  melted 
with  too  strong  a  blast,  it  is  hardened.  Iron  melted  dull  does 
not  make  a  sound  casting.  Iron  melted  with  poor  coal  or  coke 
is  injured  by  the  impurities  in  the  fuel.  Iron  melted  with  oyster 
shells,  limestone  and  other  mineral  fluxes  may  take  up  oxides, 
sulphides,  phosphides,  silicates  and  other  impurities  contained 
in  the  flux  and  be  ruined  by  them  for  foundry  work. 

The  per  cent,  of  iron  lost  in  melting  is  increased  by  improper 


144  THE   CUPOLA   FURNACE. 

melting  and  fluxing,  and  maybe  double  or  treble  what  it  should 
be.  We  have  made  a  great  many  experiments  to  ascertain  the 
effect  of  silicon  on  iron,  and  have  found  that  silicon  enters  freely 
into  combination  with  cast  iron  and  has  a  softening  effect  upon 
it.  Iron  as  hard  as  tempered  steel  may  be  made  as  soft  as  lead 
by  combining  it  with  silicon.  But  silicon  is  an  impurity  hav- 
ing a  deleterious  effect  upon  iron.  An  excess  of  it  destroys 
cohesive  force  ard  crystallization,  and  reduces  transverse  and 
tensile  strength.  So  great  is  the  destruction  of  cohesive  force 
in  cast  iron  by  silicon  that  the  strongest  iron  may  be  reduced 
to  a  powder  when  combined  with  an  excess  of  silicon.  Silicon 
in  any  proportion  is  a  detriment  to  cast  iron,  as  an  .iron.  The 
nature  and  form  of  crystallization  of  a  pure  cast  iron  is  changed 
by  sudden  cooling  in  a  mould,  and  a  soft  iron  in  the  pig  may 
become  a  hard  iron  in  a  casting,  This  chilling  property  in 
cast  iron  is  destroyed  by  silicon,  and.  an  iron  high  in  it  is 
not  hardened  when  run  into  a  sand  mould  or  upon  an  iron 
chill.  The  destruction  of  the  chilling  tendency  in  cast  iron  is 
very  desirable  in  the  manufacture  of  light  castings,  and  for  this 
reason  silicon  irons  are  largely  used  in  foundries  making  this 
class  of  work. 

The  per  cent,  of  silicon  an  iron  may  contain  and  yet  retain 
sufficient  cohesive  force  for  the  work,  depends  upon  the  amount 
of  other  impurities  in  the  iron  and  the  work  the  iron  is  em- 
ployed to  make.  For  heavy  work,  requiring  great  strength,  it 
should  contain  none  at  all.  For  light  machinery  it  may  con- 
tain from  one-half  to  one  per  cent. ;  and  for  stove  plate,  light 
bench  work,  etc.,  it  may  contain  from  two'  to  three  per  cent. 
This  amount  is  sufficient  to  reduce  the  chilling  tendency  of  the 
iron,  without  impairing  its  strength  to  any  great  extent  in  this 
class  of  work.  But  a  larger  amount  destroys  the  strength  of 
the  iron  and  also  injures  its  flowing  property  in  a  mould. 

At  the  present  time  there  is  a  large  amount  of  high  silicon 
cheap  Southern  iron  being  used  in  stove  foundries  for  the  pur- 
pose of  making  a  cheap  mixture  and  a  soft  casting.  At  one  of 
these  foundries  we  recently  visited,  the  foreman  informed  me  that 


FLUXING   OF   IRON   IN   CUPOLAS.  145 

they  were  using  a  mixture  that  cost  $14  per  ton,  and  said  their 
breakage  in  the  tumbling  barrels  and  mounting  shop  was  very 
large,  and  he  never  made  a  shipment  to  their  warehouse  in 
New  York,  a  distance  of  25  miles,  but  a  lot  of  stoves  were 
broken  in  transit  and  sent  back  to  be  remounted  and  repaired. 

At  another  stove  foundry  in  Troy,  N.  Y.,  they  informed  us 
they  were  using  a  mixture  of  Pennsylvania  irons  that  cost  them 
$20  per  ton.  They  had  scarcely  any  breakage  at  their  works, 
and  shipped  their  lightest  stoves  and  plate  to  their  warehouse 
in  Chicago  without  boxing  or  crating,  and  never  had  any  break- 
age in  transit  or  in  handling.  They  had  found  by  experience 
that  a  mixture  of  Pennsylvania  irons  at  a  cost  of  $20  per  ton 
was  cheaper  in  the  long  run  than  a  mixture  of  cheap  Southern 
irons  at  $14  per  ton. 

In  a  number  of  other  foundries  we  visited,  they  all  complained 
of  heavy  breakage  when  using  high  silicon  irons  as  softeners. 
Another  matter  to  be  considered  in  using  these  high  silicon 
irons  for  stove  plate,  is,  how  long  will  a  stove  last,  made  of  such 
weak  iron,  and  can  a  reputation  for  good  work  be  maintained 
by  foundries  using  them?  A  stove  made  of  this  kind  of  iron 
will  certainly  not  last  as  long  as  one  made  of  good  iron. 

Carbon  has  the  same  effect  upon  cast  iron  as  silicon,  in  soft- 
ening and  reducing  the  chilling  tendency.  The  hardest  of  cast 
iron  can  be  made  the  softest  by  the  addition  of  carbon,  without 
destroying  its  cohesive  force  and  rendering  it  brittle  or  rotten, 
and  carbon  can  be  added  to  iron  in  a  cupola  as  readily  as  sili- 
con. Before  the  high  silicon  Southern  irons  were  put  upon  the 
Northern  market,  highly  carbonized  irons  were  used  as  softeners 
for  stove  plate  and  other  light  work,  and  a  far  better  grade  of 
castings  were  made  then  than  now  are  made  from  the  silicon 
irons. 

It  is  difficult  to  remove  silicon  from  iron  when  melted  in  a 
cupola,  but  free  carbon  is  readily  removed  by  the  oxidizing 
flame  in  a  cupola  produced  by  a  strong  and  large  volume  of 
blast ;  and  a  soft  iron  may  be  hardened  in  melting  to  such  an 
extent  as  to  make  it  unfit  for  the  work.  This  can  be  prevented 
10 


146  THE   CUPOLA    FURNACE. 

to  some  extent  by  using  a  mild  blast  and  melting  the  iron  low 
in  the  cupola,  ^and  it  can  also  be  prevented  by  the  use  of  chem- 
icals in  the  cupola  to  produce  a  carbonizing  flame. 

We  have  spent  a  great  deal  of  time  and  money  in  experiment- 
ing on  the  production  of  such  a  flame  in  a  cupola  as  would  not 
only  prevent  the  deterioration  of  iron  in  melting,  but  would  im- 
prove its  quality,  and  at  the  present  time  are  engaged  in  the 
manufacture  of  a  chemical  compound  for  this  purpose. 

FLUOR   SPAR. 

Fluor  spar  is  extensively  used  as  a  cupola  flux,  in  sections 
of  the  country  where  it  is  found  native  and  can  be  procured  at 
a  moderate  cost,  and  it  has  also  been  used  to  a  considerable 
extent  in  other  sections  of  the  country,  but  the  expense  of 
transporting  this  heavy  material  has  greatly  retarded  its  use  as 
a  flux  at  any  great  distance  from  the  mines.  Fluor  spar  when 
used  in  sufficient  quantities  in  a  cupola,  produces  a  very  fluid 
slag  that  absorbs  and  liquefies  the  non-metallic  residue  of  melt- 
ing with  which  it  comes  in  contact;  keeps  the  cupola  open  and 
working  freely,  and  causes  it  to  dump  clean.  But  it  also  fluxes 
the  cupola  lining,  causing  it  to  burn  out  in  a  very  short  time, 
and  for  this  reason  it  can  only  be  used  in  large  quantities  with 
certain  grades  of  lining  material  that  are  only  affected  to  a  very 
limited  extent  by  it.  This  quality  of  lining  material  can  gen- 
erally be  procured  in  the  vicinity  of  the  mine,  but  it  cannot 
always  be  had  at  a  moderate  cost  in  other  parts  of  the  country, 
and  for  this  reason  it  is  frequently  used  with  limestone  to  in- 
crease the  'fluxing  properties  of  the  limestone  and  reduce  the 
injurious  effect  of  the  spar  upon  the  cupola  lining.  When  used 
in  this  way,  fluor  spar  greatly  increases  the  efficiency  of  a 
poor  limestone,  and  often  enables  a  founder  to  use  a  cheap 
limestone  that  could  not  be  employed  alone  as  a  flux,  while  the 
limestone  reduces  the  injurious  effect  of  the  spar  upon  the  lin- 
ing, and  the  two  combined  make  an  excellent  flux  for  tapping 
slag  in  long  heats. 

We  have  used  fluor  spar  in  a  number  of  cupolas  and  with  a 


FLUXING   OF   IRON   IN    CUPOLAS.  147 

great  many  different  brands  of  iron.  We  never  found  it  to  harden 
or  soften  any  of  these  irons  to  a  noticeable  extent,  but  it  im- 
proved the  melting  very  materially  in  a  number  of  cases  where 
the  cupola  was  run  beyond  its  melting  capacity,  melted  slow 
in  the  latter  part  of  the  heat,  and  could  not  be  dumped  without 
a  great  deal  of  labor. 

CLEANING    IRON    BY    BOILING. 

Before  the  use  of  fluxes  in  cupolas  was  so  well  understood 
as  at  the  present  time,  it  was  a  common  practice  in  many 
foundries  to  cleanse  iron  of  impurities  in  a  ladle  by  agitating 
or  boiling  the  molten  metal.  This  caused  a  large  amount  of 
dross  to  collect  on  the  surface,  from  which  it  was  skimmed  off 
and  the  iron  was  considered  to  be  purer  after  the  boiling.  A 
favorite  way  of  agitating  iron  in  a  ladle  was  to  place  a  raw 
potato  or  apple  on  the  end  of  a  tap  bar  and  hold  it  in  the 
molten  metal,  near  the  bottom  of  the  ladle,  for  a  short  time. 
The  potato  or  apple  contained  a  sufficient  amount  of  moisture 
to  agitate  or  boil  the  metal  gently  without  exploding  it,  and 
the  metal  was  said  to  be  greatly  benefited  by  this  gentle  boil- 
ing ;  but  practice  has  demonstrated  that  nothing  is  gained  by 
boiling  iron  in  a  ladle,  and  the  practice  has  long  since  been  dis- 
continued in  this  country. 

A  ball  of  damp  clay  placed  upon  the  end  of  a  tap  bar  was 
also  used  for  boiling  iron  in  a  ladle,  but  this  was  not  considered 
as  good  or  as  safe  as  an  apple  or  potato,  for  if  the  clay  chanced 
to  be  too  damp,  it  caused  the  iron  to  boil  violently  and  some- 
times to  explode. 

Another  favorite  way  of  cleansing  and  mixing  irons  years 
ago  was  to  pole  the  molten  iron.  This  was  done  with  a  pole 
two  or  three  inches  in  diameter,  of  green  hickory  or  other  hard 
wood.  The  pole  was  thrust  into  the  molten  metal  in  a  ladle  or 
reverberatory  furnace,  and  the  metal  stirred  with  it.  The  effect 
of  the  green  wood  thrust  into  the  metal  was  to  cause  it  to  boil 
around  the  pole,  and  as  the  pole  was  moved  through  the  meta) 
all  parts  of  the  metal  were  agitated,  and  a  better  mixture  of  the 


148  THE   CUPOLA   FURNACE. 

different  grades  of  iron  melted  was  effected  and  a  more  homo- 
geneous casting"  produced.  The  poling  of  iron  was  a  common 
practice  in  many  foundries  twenty-five  years  ago,  but  we  have 
not  seen  iron  poled  in  a  ladle  for  many  years,  and  we  believe 
the  practice  has  been  entirely  discontinued  with  cupola- melted 
iron  ;  but  poling  is  still  practiced  in  many  foundries  in  the  mix- 
ing of  iron  in  reverberatory  furnaces  for  rolls  and  other  cast- 
ings requiring  a  very  strong  homogeneous  iron. 


CHAPTER  VII. 

DIFFERENT    STYLES    OF   CUPOLAS. 
OLD   STYLE    CUPOLAS. 

BEFORE  describing  the  construction  of  the  cupolas  now  in 
use,  a  short  account  of  the  old-fashioned  cupolas  may  be  of  in- 
terest to  many  founders  who  have  not  had  an  opportunity  of 
seeing  them  or  observing  their  defects,  all  of  which  defects 
should  be  avoided  in  modern  ones. 

In  Fig  20  is  seen  the  old  style  cupola  in  general  use  through- 
out the  country  many  years  ago,  many  of  which  are  still  in  use 
in  some  of  the  old-time  small  foundries.  A  square  cast-iron 
bottom  plate,  with  opening  in  the  center  and  drop  door,  is 
placed  upon  a  brick  foundation  at  a  sufficient  height  above  the 
floor  for  the  removal  of  the  dump.  An  iron  column  is  placed 
upon  each  corner  of  the  plate,  and  upon  these  columns  is  placed 
another  cast-iron  plate,  having  an  opening  in  the  center  for  the 
top  of  the  cupola.  Upon  this  plate  a  brick  stack  is  constructed 
to  carry  off  the  flame  and  unconsumed  gases  from  the  cupola- 
The  stack  plate  was  sometimes  placed  upon  brick  columns  or 
brick  walls,  built  on  each  side  of  the  cupola,  through  which 
openings  were  made  for  manipulating  the  tuyere  elbows.  The 
stack  was  built  square  and  of  a  much  larger  size  than  the  in- 
side diameter  of  the  cupola.  It  was  not  subjected  to  a  very 
high  heat,  and  was  built  of  common  red  brick.  These  large 
stacks  were  not  built  very  high  and  threw  out  very  few  sparks 
at  the  top,  which  was  due  to  their  size.  The  cupola  was  placed 
between  the  bottom  and  stack  plate,  and  the  casing  was  formed 
of  cast-iron  staves,  which  were  held  together  by  wrought-iron 
bands,  drawn  tight  by  draw-bolts  placed  through  the  flanged 


150 


THE   CUPOLA    FURNACE. 


ends  of  the  bands.  When  the  casing  was  made  tapering,  the 
bands  were  placed  in  position  when  hot  and  shrunk  on.  The 
cupolas  were  only  from  six  to  eight  feet  high,  and  those  of 


FIG.  20. 


OLD    STYLE   CUPOLA. 


DIFFERENT    STYLES    OF   CUPOLAS.  !$! 

small  diameter  were  generally  made  larger  at  the  bottom  than 
at  the  top,  to  facilitate  dropping,  and  that  a  large  quantity  of 
molten  iron  might  be  held  in  the  cupola  for  a  heavy  casting. 
The  charging  door  was  placed  in  the  stack  just  above  the  stack 
plate.  From  two  to  four  tuyeres  were  put  upon  each  side 
of  the  cupola,  one  above  the  other,  and  from  eight  to  ten  inches 
apart.  The  tuyeres  were  supplied  from  a  blast  pipe  ^n  each 
side,  to  which  was  attached  a  flexible  leather  hose  and  tin  or 
copper  elbow  for  conducting  the  blast  into  the  tuyeres.  A 
small  hole  was  made  at  the  bend  of  the  elbow  for  looking  into 
the  tuyere,  and  closed  with  a  wooden  plug.  The  tuyeres  were 
frequently  poked  with  an  iron  bar  through  these  openings. 

When  light  work  was  to  be  cast,  the  upper  tuyeres  were 
closed  with  clay  or  loam,  and  the  blast  sent  through  the  lower 
tuyere.  When  it  was  desired  to  accumulate  a  large  amount  of 
molten  iron  in  the  cupola  for  a  heavy  piece  of  work,  the  lower 
tuyeres  were  used  until  the  molten  iron  rose  to  the  lower  edge. 
The  tuyere  elbows  were  then  withdrawn  and  shifted  to  the  next 
tuyere  above,  and  the  lower  tuyere  closed  with  clay  or  loam 
rammed  in  solid.  The  shifting  of  the  tuyere  elbows  was  con- 
tinued in  this  way  until  the  necessary  amount  of  molten  iron  for 
the  work  to  be  cast  was  accumulated  in  the  cupola.  When  a 
heavy  piece  of  work  was  to  be  cast,  a  sufficient  quantity  of  fuel 
was  placed  in  the  cupola  to  bring  the  top  of  the  bed  some 
distance  above  the  top  of  the  highest  tuyere  to  be  used  ;  on  the 
bed  two  cwt.  of  iron  was  charged,  and  a  shoveful  of  coke  and 
a  cwt.  of  iron  charged  throughout  the  heat.  The  charging  was 
raised  a  little  in  different  sized  cupolas,  but  the  fuel  and  iron 
were  always  mixed  in  charging.  The  large  body  of  molten 
metal  frequently  pressed  out  the  front  and  sometimes  the  plug- 
ging of  the  tower  tuyeres.  After  the  iron  was  tapped,  the  stock 
in  the  cupola  dropped  so  low  that  no  further  melting  could  be 
done  with  the  blast  in  the  upper  tuyeres,  and  frequently  the 
lower  tuyeres  were  so  clogged  that  they  could  not  be  opened, 
and  the  bottom  had  to  be  dropped. 

In  practice  it  was  found  that  in  a  cupola  constructed  large  at 


152  TliE   CUPOLA   FURNACE. 

the  bottom  and  small  at  the  top  for  the  purpose  of  retaining  a 
large  amount  of  molten  iron,  the  stock  did  not  spread  to  fill  the 
cupola  as  it  settled,  and  a  great  deal  of  heat  escaped  through 
the  space  made  between  the  lining  and  stock  by  the  settling  of 
the  stock.  It  was  also  found  that  the  shifting  of  tuyeres  re- 
quired such  a  high  bed  that  the  cupola  melted  slowly,  and  a 
greater  per  cent,  of  fuel  was  consumed  in  large  than  in  small 
heats.  , 

THE    RESERVOIR    CUPOLA. 

To  overcome  the  objections  to  the  tapering  cupola  and  shift- 
ing of  the  tuyeres,  and  still  be  able  to  hold  a  large  amount  of 
molten  iron  in  a  cupola,  the  reservoir  cupola,  Fig.  21,  was 
designed. 

The  casing  of  this  cupola  was  made  of  wrought  iron,  and  the 
bottom  section,  to  a  height  of  from  twelve  to  twenty- four  inches, 
was  constructed  of  one-third  greater  diameter  than  the  upper 
section  or  cupola  proper.  This  arrangement  admitted  of  a 
large  body  of  molten  iron  being  held  in  the  cupola  without 
shifting  the  tuyeres.  The  metal  was  spread  over  a  larger  sur- 
face, which  reduced  the  pressure  on  the  breast,  and  did  not 
leave  the  stock  in  so  bad  a  condition  for  melting  after  a  large 
tap  was  made  as  in  the  taper  cupola,  and  melting  could  be  con- 
tinued after  a  large  body  of  iron  was  tapped.  The  reservoir 
cupola  did  faster  and  more  economical  melting  in  large  heats 
than  the  tapered  cupola,  but  in  small  heats  the  amount  of  fuel 
required  for  the  bed  was  too  large  for  economical  melting. 

At  the  present  time  cupolas  are  made  of  the  same  diameter 
from  the  bottom  to  six  or  eight  inches  above  the  tuyeres.  The 
tuyeres  are  placed  at  a  height  to  suit  the  general  run  of  work 
to  be  done,  and  when  a  heavy  piece  is  to  be  cast,  the  iron  is 
held  in  ladles  and  covered  with  charcoal  or  small  coke  to  ex- 
clude the  air.  The  molten  iron  can  in  this  way  be  kept  in 
almost  as  good  condition  for  pouring  as  in  the  cupola,  and 
the  cupola  is  kept  in  better  condition  and  melts  faster  and 
longer. 


DIFFERENT    STYLES   OF   CUPOLAS. 
FIG.  21. 


153 


4 

1 

1 

1 

1 

1 

RESERVOIR   CUPOLA. 


154 


THE   CUPOLA   FURNACE. 


In   Fig. 


STATIONARY    BOTTOM    CUPOLA. 

shown  the  old  style  English  cupola.  This 
cupola,  is  constructed  upon  a 
solid  foundation  of  stone  or 
brick  work  and  has  a  stationary 
bottom  of  brick,  upon  which  is 
made  a  sand  bottom.  The 
refuse,  consisting  of  ash,  cinder 
and  slag,  remaining  in  the  cu- 
pola after  the  iron  is  melted,  is 
drawn  out  at  the  front  in  place 
of  dropping  it  under  the  cupola, 
as  is  now  generally  done  with 
the  drop-bottom  cupola.  These 
cupolas  are  generally  of  small 
diameter.  The  opening  in  front 
for  raking  out  is  about  two  feet 
square,  and  when  the  cupola  is 
in  blast,  is  covered  with  an  apron 
of  wrought  iron.  When  the 
cupola  has  been  made  up  for  a 
heat,  shavings,  firewood  and  a 
small  amount  of  coke  are  placed 
in  it  and  ignited  with  the  front 
open ;  when  the  coke  is  well 
alight,  a  wall  is  built  up  with 
pieces  of  coke  even  with  the 
inside  of  the  cupola  lining. 

FIG.  23. 


STATIONARY  BOTTOM  CUPOLA. 


APRON. 


DIFFERENT   STYLES    OF   CUPOLAS.  155 

The  bed  of  coke  is  then  put  in,  a  round  stick  is  placed  in  the 
spout  to  form  the  tap  hole,  and  the  front  is  then  filled  in  with 
new  molding  sand  or  loam  even  with  the  casing,  and  rammed 
solid.  The  apron,  Fig.  23,  is  then  placed  in  position  over  the 
loam  and  wedged  tight  against  it,  to  prevent  it  being  forced 
out  by  the  pressure  of  molten  iron  in  the  cupola.  After  the 
breast-plate  is  placed  in  position,  the  tap  hole  and  spout  are 
made  up  in  the  ordinary  way.  Some  melters  prefer  to  place 
the  apron  in  position  before  lighting  the  fire,  and  put  the  breast 
in  from  the  inside  when  making  up  the  sand  bottom.  It  is  then 
rammed  solid  against  the  apron  and  made  up  to  the  full  thick- 
ness of  the  brick  lining  of  the  cupola.  When  the  heat  has  been 
melted  the  breast-plate  is  removed  and  the  loam  front  dug  out. 
After  the  loam  front  has  been  broken  away,  a  sheet-iron  fender 
is  placed  in  front  of  the  cupola  to  protect  the  workmen  from 
the  heat,  and  the  raking  out  process  begins.  This  is  done  by 
two  men  with  a  long  two- pronged  rake.  If  the  refuse  hangs  in 
the  cupola,  it  is  broken  down  from  the  charging  door  with  a 
long  bar  or  by  throwing  in  pieces  of  pig  iron.  These  cupolas 
were  extensively  used  in  England,  but  never  to  any  extent  in 
this  country.  We  saw  one  in  Baltimore  a  few  years  ago,  and 
believe  this  is  the  only  one  in  use  in  this  country ;  but  they 
are  still  in  general  use  in  England. 

EXPANDING   CUPOLA. 

Fig.  24  is  a  sectional  elevation  of  the  expanding  cupola, 
which  is  said  to  have  melted  very  rapidly  and  with  very 
little  fuel.  This  peculiar  form  was  designed  to  admit  of  the 
charging  of  a  large  quantity  of  iron  before  putting  on  the  blast, 
for  the  purpose  of  utilizing  all  the  heat  produced  by  the  com- 
bustion of  the  fuel.  These  cupolas  were  built  of  common  brick, 
banded  with  wrought-iron  bands  and  lined  with  firebrick.  The 
diameter  at  the  charging  door  was  sixty  inches  and  at  the 
tuyeres  thirty  inches,  or  one-half  the  diameter  at  the  charging 
door.  Below  the  tuyeres  the  lining  expanded  to  forty  or  even 
fifty  inches,  to  give  room  for  molten  metal.  The  bottom  was 


156 


THE   CUPOLA   FURNACE. 
FIG.  24. 


EXPANDING   CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS.  157 

stationary,  and  the  refuse  after  melting  was  drawn  at  the  front. 
The  cupola  expanded  from  a  level  a  little  above  the  tuyeres  to 
the  bottom  of  the  charging  door,  thence  to  the  top  of  the  stack 
it  gradually  contracted. 

The  greatly  increased  diameter  at  the  charging  door  certainly 
admitted  of  a  large  quantity  of  iron  being  placed  in  the  cupola 
at  one  time,  and  the  utilization  of  a  very  large  per  cent,  of  the 
heat  in  melting.  The  even  taper  of  the  lining  insured  the  even 
settling  of  the  stock,  so  that  good  melting  should  have  been 
done  in  this  cupola;  but  the  best  results  obtained  appear  to 
have  been  about  six  and  a  half  pounds  of  iron  to  the  pound  of 
coke. 

This  old  form  might  be  used  to  advantage  in  the  construc- 
tion of  very  large  cupolas ;  but  in  the  ordinary  sized  cupola, 
practically  the  same  results  are  obtained  by  boshing  or  con- 
tracting the  lining  at  the  tuyeres,  and  making  it  straight  from 
the  top  of  the  boshes  to  the  charging  door. 

IRELAND'S  CUPOLA. 

Ireland's  cupola,  for  which  the  inventor  took  out  a  number 
of  patents  in  England  about  1856,  and  which  was  largely  used 
there  about  that  time,  was  constructed  of  a  variety  of  shapes 
and  sizes,  but  probably  the  best  design  is  that  shown  in  sec- 
tional view  Fig.  25.  It  is  built  with  a  bosh  and  contraction  of 
the  diameter  at  the  tuyeres,  and  has  a  cavity  of  enlarged  diame- 
ter below  them  to  give  increased  capacity  for  retaining  molten 
metal  in  the  cupola. 

The  cupola,  of  which  a  section  is  shown,  was  twenty-five  feet 
high  from  bottom  plate  to  top  of  stack,  twelve  feet  from  bottom 
plate  to  sill  of  charging  door.  The  shell  was  parallel  and  fifty 
inches  diameter  to  the  charging  door,  thence  it  gradually 
tapered  to  two  feet  three  inches  at  the  top.  There  were  two 
rows  of  tuyeres  eighteen  inches  apart,  eight  in  the  upper  row 
two  inches  diameter,  and  four  in  the  lower  row  six  inches 
diameter.  The  cupola  was  constructed  with  stationary  bottom 
and  draw  front. 


158 


THE  CUPOLA  FURNACE. 

FIG.  25. 


IRELAND'S  DOUBLE  TUYERE  CUPOLA. 


DIFFERENT   STYLES    OF   CUPOLAS.  159 

•  It  was  at  first  proposed  to  use  a  hot  blast  in  the  top  row  of 
tuyeres,  but  it  was  found  to  be  difficult  and  expensive  to  heat 
the  blast,  and  that  nothing  was  gained  by  using  the  upper  row 
with  a  cold  blast,  and  they  were  closed  and  the  cupola  con- 
structed with  only  the  lower  row  of  tuyeres.  The  interior  shape 
was  slightly  modified  to  give  more  space  for  retaining  molten 
metal,  while,  at  the  same  time,  retaining  the  boshes  and  in- 
creasing the  diameter  of  the  bottom  of  the  cupola,  as  seen  in 
the  Fig.  25.  Two  of  these  cupolas  were  used  by  the  Bolton 
Steel  and  Iron  Company  in  England,  in  melting  the  iron  for  a 
large  anvil  block  weighing  two  hundred  and  five  tons,  for  which 
two  hundred  and  twenty  tons  of  metal,  including  eight  tons 
Bessemer  steel,  were  used. 

The  cupolas  were  each  seven  feet  outside  diameter,  three  feet 
nine  inches  diameter  below  the  boshes  in  the  crucible,  and  five 
feet  diameter  above  and  below  the  crucible.  The  blast  was  sup- 
plied from  an  external  air-chamber,  extending  round  the  casing 
and  delivered  into  the  cupolas  through  two  rows  of  tuyeres 
placed  eighteen  inches  apart,  sixteen  in  the  upper  row  of  three 
inches  diameter,  and  four  in  the  lower  row  of  eight  inches  diam- 
eter. The  metal  was  melted  in  ten  hours  and  forty-five  minutes 
from  the  time  of  putting  on  the  blast  until  the  mold  was  filled, 
and  only  one  hundred  and  twenty-five  pounds  of  coke  con- 
sumed per  ton  of  metal.  Slag  was  tapped  from  the  slag  hole 
A  below  the  tuyeres  throughout  the  heat. 

IRELAND'S  CENTER  BLAST  CUPOLA. 

In  Fig.  26  is  seen  a  sectional  elevation  of  Ireland's  cupola 
with  bottom  tuyere.  The  height  from  bottom  plate  to  top  of 
stack  is  twenty-seven  feet,  from  bottom  plate  to  sill  of  charging 
door  twelve  feet.  The  casing  is  parallel  from  the  bottom  plate 
to  charging  door,  and  thence  it  gradually  tapers  to  the  top ; 
diameter  of  casing  up  to  charging  door  four  feet  six  inches, 
tapering  to  two  feet  six  inches  at  the  top  of  stack.  The  inside 
diameter  at  bottom  of  crucible,  on  the  cupota  hearth  L  is  two 
feet  six  inches,  contracting  to  two  feet  three  inches  at  spring  of 


i6o 


THE   CUPOLA   FURNACE. 
FIG.  26. 


IRELAND'S  CENTER  BLAST  CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS. 


the  bosh  AA,  and  three  feet  nine  inches  diameter  from  top  of 
bosh  to  charging  door,  whence  it  tapers  to  one  foot  nine  inches 
at  top  of  stack.  Height  of  crucible  four  feet  five  inches,  length 
of  boshes  from  AA  to  BB,  eighteen  inches  ;  height  from  top  of 
bosh  to  charging  door,  six  feet  seven  inches.  The  blast  is  sup- 
plied from  one  tuyere  placed  in  the  center  of  the  bottom  of 
crucible. 

The  tuyere  hole  through  the  iron  bottom  is  nine  inches 
diameter,  into  which  is  passed  a  seven  and  a  half-inch  water 
tuyere,  the  mouth  of  which,  H,  is  two  feet  above  the  sand  bottom 
L.  A  slag  hole  N,  five  inches  diameter,  is  placed  just  below 
the  level  of  the  mouth  of  the  tuyere.  P  is  the  tap-hole  and 
spout. 

This  cupola  melted  three  tons  of  iron  per  hour  with  two  and 
a-half  cwt.  of  coke  per  ton,  but  it  does  not  appear  to  have  given 
satisfaction,  for  it  never  came  into  general  use  in  England  or 
this  country,  and  Mr.  Ireland  changed  his  plans  and  con- 
structs his  cupolas  with  side  tuyeres. 

VOISIN'S  CUPOLA. 

In  illustration  Fig.  27  is  seen  a  sectional  elevation  of  Voisin's 
cupola,  in  which  very  good  melting  has  been  done.  The  shell 
is  constructed  of  boiler  plate  with  an  external  air  chamber  of 
the  same  material,  extending  all  the  way  round  the  body  of  the 
cupola.  This  air  chamber  is  supplied  from  two  pipes,  one  on 
each  side  of  the  cupola.  Two  sets  of  tuyeres  lead  from  the  air 
belt  into  the  cupola.  The  lower  set  are  oblong,  four  in  number, 
placed  at  equal  distances  apart  and  at  right  angles  to  the  air 
belt.  The  upper  set  are  round,  of  less  capacity  than  the  lower 
set,  are  placed  horizontally  through  the  lining  and  diagonally 
to  the  lower  set,  so  that  they  are  between  them  at  a  higher  level. 

Mr.  Voisin  claims  through  this  arrangement  of  the  tuyeres, 
that  the  escaping  gases  are  burnt  in  the  cupola,  creating  a 
second  zone  of  fusion  with  those  gases  alone,  and  the  second 
set  of  tuyeres  obviates  to  some  extent  the  evil  effect  of  the 
formation  of  carbonic  oxide  in  the  cupola. 
1  1 


1 62 


THE   CUPOLA   FURNACE. 
FIG.  27. 


VOISIN'S   CUPOLA. 


DIFFERENT    STYLES    OF    CUPOLAS.  163 

This  cupola  is  constructed  in  slightly  varying  shapes  inside 
the  lining,  but  the  following  dimensions  give  a  general  outline 
of  it :  Vertical  dimensions  from  bottom  to  offset  below  tuy- 
eres, one  foot  ten  inches ;  offset  below  tuyeres  to  lower  end 
of  bosh,  two  feet  four  inches ;  length  of  bosh,  one  foot  two 
inches ;  top  of  bosh  to  charging  door,  six  feet  ten  inches ; 
bottom  of  charging  door  to  bottom  of  stack,  two  feet  seven 
inches ;  taper  to  stack,  three  feet  ten  inches.  Horizontal  di- 
mensions:  Below  tuyeres,  two  feet;  at  tuyeres,  one  foot  eight 
inches;  at  top  of  bosh,  two  feet  four  inches;  at  bottom  of 
charging  door,  one  foot  ten  inches ;  at  charging  door,  two  feet 
seven  inches. 

The  casing  is  made  straight  from  the  bottom  plate  to  taper  to 
the  stack,  and  to  get  the  above  dimensions  it  has  to  be  lined 
with  brick  made  specially  for  this  cupola. 

Mr.  Voisin  has  invented  a  number  of  different  cupolas,  but 
this  one  is  said  in  melting  to  give  the  best  results. 

WOODWARD'S  STEAM-JET  CUPOLA. 

In  Fig.  28  is  seen  a  sectional  view,  showing  the  construction 
of  the  Woodward  steam  jet  cupola,  in  use  to  some  extent  in 
England.  This  cupola  is  worked  by  means  of  an  induced  cur- 
rent or  strong  draught  caused  by  a  steam-jet  blown  up  the 
cupola  stack,  which  is  very  much  contracted  just  above  the 
charging  door.  There  are  several  different  modes  of  applying 
the  steam-jet,  but  the  general  principle  will  be  at  once  under- 
stood from  the  figure  (28).  The  cupola  is  constructed  upon 
the  general  plan  of  the  English  cupola,  with  a  stationary  bot- 
tom and  draw  front.  Two  rows  of  tuyeres  or  air-inlets,  as  they 
are  termed,  are  placed  radially  at  two  different  levels.  In  the 
lower  row  there  are  four  openings,  varying  in  size  from  five 
to  eight  inches  in  diameter,  according  to  the  size  of  the  cupola. 
In  the  upper  row  there  are  eight,  varying  in  diameter  from  three 
to  five  inches.  Each  of  the  air-inlets  is  provided  with  a  cover 
outside,  which  can  be  closed  when  it  is' desired  to  shut  off  the 
draught.  The  upper  row  of  air-inlets  is  placed  from  ten  to 


1 64 


THE  CUPOLA  FURNACE. 
FIG  28. 


WOODWARD'S  STEAM -JET  CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS.  165 

fifteen  inches  above  the  lower  row.  The  lining  is  contracted  at 
the  air-inlets  to  throw  the  air  to  the  center  of  the  stock,  and  en- 
larged below  the  air-inlets  to  admit  of  the  retention  of  a  large 
amount  of  molten  iron  in  the  cupola. 

The  charges  of  fuel  and  iron  are  put  in  at  the  charging  door 
A  in  alternate  layers  in  the  ordinary  way,  and  the  door  tightly 
closed  and  luted  to  prevent  the  admission  of  any  air.  The 
steam  is  then  turned  on  through  the  nozzle  B  connected  with 
the  boiler  by  steam-pipe  D,  and  the  air-inlets  N  opened  for  the 
admission  of  air.  When  the  cupola  is  working,  the  draught 
has  to  be  regulated  by  the  melter  and  care  taken  to  close  any 
air-inlets  near  which  iron  is  seen  to  accumulate  in  a  semi-fluid 
state.  The  temperature  at  the  spot  where  the  iron  chills  will 
soon  rise  to  a  degree  that  will  cause  the  iron  to  run  freely,  when 
the  air-inlet  may  be  again  opened.  All  the  iron  to  be  melted 
is  put  in  and  the  door  closed  before  the  steam  is  turned  on- 
The  charging  may  be  continued  throughout  the  heat,  but  the 
opening  of  the  door  has  the  same  effect  on  the  stock  as  shutting 
off  the  blast  in  the  ordinary  cupola,  and  the  melting  stops.  The 
repeated  opening  of  the  door  soon  gets  the  cupola  into  bad 
working  order  and  it  bungs  up  in  a  short  time. 

When  it  is  desired  to  use  the  cupola  for  continuous  melting 
or  for  a  larger  amount  of  iron  than  can  be  put  in  at  one  time,  it 
is  constructed  with  a  side  flue  and  feeding  hopper,  as  shown  in 
Fig.  29.  The  general  construction  and  air  inlets  are  the  same  as 
those  shown  in  Fig.  28.  The  stack  is  removed  and  the  feeding 
hopper  A  with  a  sliding  door  B  at  the  bottom,  to  be  worked  by 
the  lever  D,  is  placed  on  top  of  the  cupola.  The  flue  H  near 
the  top  of  the  cupola  connects  it  with  the  stack  M,  and  the 
draught  is  induced  by  a  steam-jet  from  the  nozzle  N  attached 
to  the  steam-pipe  P.  When  filling  the  cupola,  the  bottom  of 
the  hopper  is  left  open  and  the  charges  put  in  in  the  ordinary 
way  until  the  cupola  is  filled.  The  bottom  door  of  the  hopper 
is  then  closed,  and  when  the  cupola  is  melting  the  charges  of 
fuel  and  iron  are  put  into  the  hopper  and  dropped  into  the 
cupola  as  the  stock  settles,  and  the  door  is  at  once  closed  to 
exclude  the  air  at  the  top  of  the  cupola. 


1 66 


THE   CUPOLA   FURNACE. 
FIG.  29. 


WOODWARD'S  STEAM-JET  CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS.  l6/ 

It  is  asserted  by  those  interested  in  this  cupola  that  it  effects 
a  great  saving  in  fuel  over  the  ordinary  blast  cupola.  The  con- 
sumption of  coke  in  melting  a  ton  of  iron  is  placed  at  one  hun- 
dred and  fifty  pounds,  a  very  low  rate  of  fuel ;  but  the  same 
results  are  also  claimed  to  have  been  obtained  in  blast  cupolas 
of  good  design  when  properly  worked. 

The  steam  required  to  create  the  draught  is  only  equal  in 
quantity  to  what  would  be  required  by  an  engine  for  driving  a 
fan  or  blower  of  sufficient  power  to  work  an  ordinary  cupola  of 
the  same  size.  Considerable  saving  is  effected  in  the  first  cost 
of  engine  and  fan  or  blower,  besides  the  saving  in  wear  and  tear 
of  machinery. 

The  objection  to  this  style  of  cupola  is  the  slow  melting,  for 
it  cannot  be  forced  beyond  a  certain  point,  and  when  a  large 
amount  of  iron  is  to  be  melted  the  cupola  must  be  kept  work- 
ing all  day.  This  does  not  meet  the  views  of  the  foundrymen 
of  this  country,  who  desire  to  melt  their  heats  in  from  one  to 
two  hours  from  the  time  the  blast  is  put  on  until  the  bottom  is 
dropped,  and  with  that  object  in  view  construct  their  cupolas. 

TANK  OR  RESERVOIR  CUPOLA. 

In  Fig.  30  is  seen  a  sectional  elevation  of  a  reservoir  cupola. 
This  cupola  was  designed  for  the  purpose  of  making  soft  iron 
for  light  castings.  It  only  differs  in  construction  from  the 
ordinary  type  in  the  reservoir  or  tank  placed  in  front,  which 
may  be  attached  to  any  cupola. 

The  cupola  is  set  high  and  the  tank  A  is  placed  in  front  of 
it,  with  the  cupola  spout  leading  into  it  near  the  top.  The 
molten  iron  is  run  from  the  cupola  into  the  tank  as  fast  as 
melted,  and  drawn  from  the  tank-spout  into  the  ladles  as  it  may 
be  required  for  pouring.  The  tank  is  made  of  boiler  plate  and 
lined  with  fire-clay  or  other  refractory  material,  and  is  covered 
with  an  iron  lid,  lined  likewise  with  same  material.  The  spout 
and  breast  are  made  up  the  same  as  for  an  ordinary  cupola. 
Before  putting  on  the  blast,  the  tank  is  filled  with  charcoal  and 
closed  with  the  cover ;  and  as  the  iron  melts,  it  is  run  into  the 


1 68 


THE   CUPOLA   FURNACE. 
FIG.  30. 


TANK  OR  RESERVOIR  CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS.  169 

tank,  where  it  is  allowed  to  remain  a  sufficient  length  of  time  to 
be  carbonized  and  softened  by  the  charcoal. 

These  cupolas  have  been  constructed  in  a  number  of  dif- 
ferent ways ;  the  tank  has  been  made  of  sufficient  size  to  hold 
the  entire  heat  of  molten  iron  before  pouring,  so  that  the  iron 
might  be  of  an  even  grade  throughout  the  heat  and  softened  to 
a  greater  extent;  and  they  have  been  riveted  to  the  cupola 
casing  and  the  lining  continued  from  the  cupola  to  the  tank. 
In  this  latter  case,  the  top  is  bolted  or  clamped  to  the  tank  and 
a  tight  joint  made  to  prevent  the  escape  of  the  blast,  which  has 
the  same  pressure  in  the  tank  as  in  the  cupola. 

The  tank  cupola  produces  a  softer  iron  than  the  ordinary 
cupola,  but  there  is  considerable  additional  expense  attached  to 
it  in  keeping  up  the  tank  and  supplying  it  with  charcoal. 
Another  objection  is  the  change  made  in  the  shrinkage  of  the 
iron  ;  that  taken  from  the  tank  shrinks  less  than  the  same  grade 
of  iron  when  taken  from  the  cupola,  and  when  some  parts  of  a 
machine  or  stove  are  made  from  the  tank  and  other  parts  from 
the  cupola,  allowance  must  be  made  in  the  patterns  for  the 
difference  in  shrinkage. 

It  is  claimed  by  some  founders  that  soft  iron  can  be  produced 
by  putting  a  quantity  of  charcoal  on  the  sand  bottom,  and 
placing  the  shavings  and  wood  for  lighting  the  bed  on  top  of 
the  charcoal.  In  lighting  up,  the  charcoal  is  not  burned,  but 
remains  in  the  cupola  during  the  heat  and  may  be  found  in  the 
dump.  This  is  the  case  if  the  tuyeres  are  high  and  the  front  is 
closed  before  lighting  up,  but  if  the  tuyeres  are  low  or  the  front 
and  tap-hole  are  not  closed,  the  charcoal  will  be  burned  out  in 
lighting  up  the  bed,  the  same  as  the  wood. 

Tanks  are,  in  England,  used  in  connection  with  cupolas  to 
some  extent  at  the  present  time  for  mixing  irons  or  to  enable 
the  founder  to  run  a  large  casting  or  heat  from  a  small  cupola. 
The  iron  for  an  entire  heat,  requiring  several  hours  to  melt  in  a 
small  cupola,  is  melted  and  run  into  the  tank  and  drawn  from 
the  tank  into  the  ladles  at  casting  time.  This  makes  a  well- 
mixed  and  even  grade  of  iron  in  all  the  castings  and  saves  con- 


1 70  THE   CUPOLA   FURNACE. 

siderable  time  in  casting,  as  the  moulders  are   not  obliged  to 
wait  for  iron  to  melt,  as  is  often  the  case. 

MACKENZIE  CUPOLA. 

In  Fig.  3 1  is  shown  a  sectional  elevation  of  the  Mackenzie 
Cupola,  designed  by  Mr.  Mackenzie,  a  practical  foundryman, 
and  manufactured  by  Isbel-Porter  Co.,  Newark,  N.  J.  When 
this  cupola  was  designed  the  only  one  in  use  was  the  common 
straight  one  with  a  limited  number  of  very  small  tuyeres  and  low 
charging  doors,  and  it  melted  very  slowly.  It  was  the  custom  in 
foundries  at  that  time,  to  put  on  the  blast  at  one  or  two  o'clock 
and  blow  all  the  afternoon  in  melting  a  heat.  Moulders  gen- 
erally stopped  moulding  when  the  blast  went  on  and  a  great 
deal  of  time  was  lost  in  waiting  for  iron.  To  save  this  time  and 
get  a  few  hours'  more  work  from  each  moulder  on  casting  days, 
Mr.  Mackenzie  conceived  the  idea  of  constructing  a  cupola  that 
would  melt  a  heat  in  two  hours  from  the  time  the  blast  was  put 
on  until  the  bottom  was  dropped.  He  had  discovered  that  the 
tuyeres  in  common  use  were  too  small  to  admit  blast  freely  and 
evenly,  and  cupolas  did  not  melt  so  well  in  the  center  as  near 
the  lining  and  tuyeres.  To  overcome  this  fault  in  the  old 
cupola,  and  admit  the  blast  to  the  stock  evenly  and  freely,  a 
belt  tuyere  was  put  in  extending  around  the  cupola,  and  to 
place  the  blast  nearer  to  the  center  of  the  cupola  at  the  tuyeres, 
the  lining  was  contracted  or  boshed  at  this  point.  To  avoid  re- 
ducing the  capacity  for  holding  molten  iron  below  the  tuyeres, 
the  lining  just  above  the  tuyeres  was  supported  by  an  apron 
riveted  to  the  cupola  casing  and  the  bosh  made  to  overhang 
the  bottom,  leaving  the  cupola  below  the  tuyeres  of  the  same 
diameter  as  before  boshing. 

This  cupola,  when  first  introduced,  was  knpwn  as  the  two- 
hour  cupola  and  wrought  a  great  revolution  in  melting  and  in 
foundry  practice.  Heats  that  had  required  half  a  day  to  melt 
were  melted  in  two  hours,  the  quantity  of  fuel  consumed  in  melt- 
ing was  reduced,  the  number  of  moulds  put  up  by  each  moulder 
increased,  and  the  cost  of  producing  castings  greatly  reduced 


DIFFERENT    STYLES    OF   CUPOLAS. 
FIG.  31. 


I/I 


MACKENZIE  CUPOLA. 


172 


THE   CUPOLA   FURNACE. 


Many  of  these  cupolas  are  still  in  constant  operation,  and  for 
short  heats  of  one  or  two  hours,  are  probably  the  most  eco- 
nomical melting  ones  now  in  use.  In  long  heats  the  tendency 
of  the  cupola  to  bridge  at  the  bosh  is  so  great,  that  it  melts 
slowly  toward  the  end  of  a  heat  and  is  frequently  difficult  to 
dump,  especially  if  the  cupola  is  a  small  one. 

We  have  had  much  experience  in  melting  in  these  cupolas, 
and  have  found  that  slag  and  cinder  adhere  to  the  lining  over 

FIG.  32. 


the  tuyeres  and  become  very  hard  and  difficult  to  remove,  and 
if  care  be  not  taken  to  remove  them  after  every  heat  it  soon 
builds  out,  as  shown  in  Fig.  32,  which  reduces  the  melting 
capacity  very  much,  and  increases  the  tendency  of  the  cupola 
to  bridge  and  hang  up.  The  lining  should  be  kept  as  near 


DIFFERENT   STYLES    OF   CUPOLAS.  1/3 

the  shape  shown  in  Fig.  31  as  possible,  and  all  building  out 
over  the  tuyeres  and  bellying  out  in  the  melting  zone,  as  far  as 
possible,  prevented. 

In  the  illustration  (Fig.  31)  is  shown  the  cupola  pit,  com- 
monly placed  under  cupolas  when  they  are  set  very  low  for 
hand-ladle  work.  The  outlet  to  the  pit  may  be  placed  at  the 
front,  back  or  side  of  the  cupola  as  found  most  convenient  for 
removing  the  dump. 

THE  HERBERTZ  CUPOLA.* 

The  cupolas  generally  used  either  for  melting  iron  or  for  any 
other  purpose,  are  cupolas  blown  through  one  or  several  rows 
of  tuyeres  inserted  at  some  distance  above  the  hearth.  The 
pressure  of  the  blast  varies  in  most  cases  from  l/£  pound  to  I 
pound,  and  the  blast  is  obtained  by  blowing  engines  or  blowers 
driven  through  belting  and  shafting  by  special  steam  engines. 
Such  a  plant,  requiring  as  it  does  many  mechanical  appliances, 
consequently  subject  to  continual  care  and  repairs,  is  expensive. 
The  Herbertz  cupola,  instead  of  being  blown  by  blast  forced 
from  below  through  the  melting  material,  is  provided  at  its 
upper  end  with  a  steam-jet  pipe,  which  in  action  creates  a 
vacuum  of  from  3  inches  to  4  inches  of  water  in  the  upper  re- 
gion of  the  cupola,  while  the  air  is  allowed  to  enter  freely  at  the 
lower  part  through  an  annular  opening  between  the  movable 
hearth  and  the  upper  shaft. 

The  movable  hearth,  as  shown  in  Fig.  33,  is  mounted  on  four 
screws,  which  by  their  common  action  lower  or  raise  it  at  will, 
and  thereby  allow  of  a  complete  and  easy  regulation  of  the 
quantity  of  blast  introduced  through  the  annular  opening.  The 
screws  work  either  in  the  standards  of  the  cupola,  as  seen  in 
Fig.  33,  or  are  carried  on  a  special  car  together  with  the  hearth, 
so  that  this  latter  can  be  removed  at  any  moment  from  under- 
neath the  shaft.  The  steam -jet  is  applied  in  the  center  line  of 
the  smoke  pipe,  which  connects  the  cupola  either  directly  with 
a  special  stack  or  is  built  like  the  down-comer  of  a  blast  furnace, 

*  By  J.  B.  Nau,  New  York. 


174 


THE    CUPOLA    FURNACE. 
FIG.  33. 


SECTION  OF  HERBERTZ'S  IRON-MELTING  CUPOLA. 


DIFFERENT   STYLES   OF   CUPOLAS.  175 

and  connects  the  cupola  with  a  horizontal  underground  flue  lead- 
ing to  any  chimney.  The  top  of  the  cupola  is  provided  with  a 
hopper  hermetically  closed  while  the  melting  is  proceeding,  and 
only  open  at  regular  intervals  and  for  a  very  short  time,  when 
the  charge  is  being  introduced. 

The  bottom  of  the  hearth  is  provided  with  a  door  turning  on 
hinges  and  kept  tight  by  a  lock.  This  door,  once  lowered  after 
the  melting  is  done,  turns  around  the  hinges  and  the  contents 
of  the  cupola  are  dropped  into  an  ash  pit,  where,  after  having 
been  cooled  with  water,  the  unburnt  coke  can  be  collected  and 
saved  for  the  lighting  of  the  cupola  in  the  next  melting. 

Three  tuyeres  are  placed  all  around  at  the  level  of  the  bottom 
of  the  hearth.  These  tuyeres,  as  we  shall  see  later  on,  are 
plugged  up  with  sand  during  the  melting,  but  are  used  before 
the  melting  in  the  kindling  of  the  fire  and  to  give  access  to  the 
air  necessary  for  combustion. 

The  shaft  is  provided  at  two  different  levels  with  bull's-eyes, 
through  which  the  fire  can  be  watched. 

The  application  of  a  steam-jet  to  create  draft  in  the  cupola 
has  many  advantages.  The  only  mechanical  appliance  re- 
quired is  a  small  boiler  supplying  the  necessary  steam  for  the 
ejector.  No  blowing  engine  or  steam  engine  with  blower,  shaft- 
ing, pulleys,  belts,  no  blast  pipe  connecting  the  blower  with  the 
cupola,  is  necessary.  The  only  repairs  are  those  on  the  boiler 
and  steam  pipe,  very  light  indeed,  without  mentioning  the  fact 
that  oil  for  lubricating  will  be  entirely  dispensed  with.  But  be- 
sides these  already  important  advantages,  some  other  features 
are  met  with.  Most  of  the  blowers,  running  at  a  speed  of  from 
1000  to  1 200  revolutions  or  more  per  minute,  produce  some- 
times a  noise,  which  often  can  be  heard  at  a  great  distance.  The 
Herbertz  cupola  runs  without  any  appreciable  noise,  and  can  be 
established  in  any  populous  center  without  the  slightest  incon- 
venience to  the  neighborhood.  Its  top  being  closed,  no  sparks 
or  flame  are  thrown  out.  The  repairs  to  the  movable  hearth 
are  very  easy  and  can  be  done  outside. 

In  the  United  States  it  is  as  yet  little  known.     For  some 


THE   CUPOLA   FURNACE. 

time,  however,  tests  have  been   made   with  it  at  a  car-wheel 
foundry  in  Elizabethport,  N.  J. 

This  cupola  is  very  well  adapted  for  the  melting  of  pig  iron. 
The  very  reduced  consumption  of  coke,  claimed  by  the  inventor 
to  be  as  low  as  4  to  5  per  cent,  of  the  weight  of  iron  (or  in 
other  words,  I  pound  of  coke  would  be  enough  to  melt  20 
pounds  of  iron),  leads  to  the  conclusion  that  the  combustion 
of  coke  must  be  complete,  or  that  the  coke  must  be  burnt  com- 
pletely to  carbonic  acid,  and  thus  generate  the  greatest  possi- 

FIG.  34. 


HORIZONTAL  SECTION. 

ble  amount  of  heat.  In  order  to  prove  this,  test-heats  have 
been  made  in  Europe,  and  the  analyses  of  the  escaping  gases 
showed  that  in  most  cases  the  whole  amount  of  carbon  was 
burnt  to  carbonic  acid,  while  in  a  few  other  cases  a  very  small 
proportion  of  carbon  burnt  to  carbonic  oxide.  In  one  of  these 
test-heats  the  mixture  in  the  cupola  was  1050  kg.*  of  Luxem- 
burg foundry  iron  No.  3  and  450  kg.  of  foundry  scrap,  a  total 
of  1500  kg.,  or  1.5  tons. 

*  i  kilogramme  =  2.2  Ibs. 


DIFFERENT    STYLES    OF   CUPOLAS. 

The  melting  coke  was  air  dry  and  contained  but  3  per  cent, 
of  water,  6.8  per  cent,  of  ash  and  1.037  Per  cent,  of  sulphur; 
190  kg.  of  filling  coke  was  put  in  the  cupola  and  on  top  of  it 
1000  kg.  of  pig  iron.  The  total  amount  of  coke  used,  including 
lighting  coke,  was  215  kg.  to  1500  kg.  pig  iron.  After  the 
fusion  was  done,  67  kg.  of  coke  were  taken  out  and  could  be  used 
again  for  the  next  day's  charge,  so  that  the  real  amount  of  coke 
used  was  only  215 — 67=  148  kg.,  or  9.9  per  cent.,  whereas  the 
real  amount  of  melting  coke  was  only  5  per  cent. 

A  careful  weighing  of  the  iron  cast  showed  that  1460  kg.,  or 
97-33  Per  cent,  of  the  original  iron  charged,  was  obtained,  con- 
stituting a  loss  of  only  2.66  per  cent.  The  temperature  of  the 
molten  metal  was  high,  and  amounted  in  part  to  1300°.  The 
escaping  gases  had  the  following  composition : 

Carbonic  Carbonic     Oxygen.     Nitrogen, 

acid.  oxide. 

Before  the  steam-jet  was  acting 7.1  o               7.1               85.8 

Five  minutes  after  steam- jet  was  acting  13.1  o               6.5               80.3 
Twenty-five    minutes    after    steam-jet 

was  acting 9.25  o              7.0              83.75 

At  the  end  of  the  cast  (after  35  min- 
utes     13.3  o               6.3               804 

Average 10.71  o  6.73  82.60 

Another  test  heat  with  thoroughly  wet  gas  coke  was  made. 
This  coke  contained  nearly  20  per  cent,  of  water  and  7.5  per 
ctnt.  of  ash.  About  12.7  per  cent,  of  it  was  used  (lighting  and 
melting  coke  together).  The  loss  in  iron  in  this  charge. was 
only  3.45  per  cent.  The  average  composition  of  the  gases  was 
11.5  of  carbonic  acid,  3.4  of  carbonic  oxide,  8.2  of  oxygen,  76.9 
of  nitrogen.  It  will  be  seen  that  in  this  last  heat  carbon  did  not 
burn  entirely  to  carbonic  acid,  which  was  probably  due  to  the 
increased  amount  of  coke  that  had  been  charged  intentionally. 

Nevertheless,  the  composition  of  these  gases  is  still  far  more 
favorable  than  would  be  obtained  with  an  ordinary  blown  cu- 
pola, where  a  certain  number  of  analyses  have  shown  that  the 
escaping  gases  contain  from  12.50  to  19.90  per  cent,  of  car- 

12 


178  THE   CUPOLA   FURNACE. 

bonic  acid  and  4.80  to  11.73  per  cent,  of  carbonic  oxide.  The 
analyses  show,  furthermore,  that  in  the  case  of  the  Herbertz  cu- 
pola, the  fuel  is  thoroughly  utilized  and  yields  the  maximum  of 
heat. 

To  obtain  such  complete  combustion  it  is  necessary  that  the 
air  should  be  in  slight  excess,  and  that  this  actually  happens  is 
shown  by  the  presence  in  the  gases  of  a  certain  amount  of  free 
oxygen.  Several  reasons  have  been  advanced  to  explain  this 
complete  combustion  of  carbon  to  carbonic  acid.  The  first  is 
that  the  air  enters  the  cupola  all  around  the  circumference  in  a 
thin  sheet  and  gives  rise  to  very  uniform  combustion.  Another 
reason  is  the  very  reduced  velocity  with  which  the  gases  rise. 

In  the  ordinary  blown  cupola  these  gases  are  pushed  upward 
with  great  pressure  and  velocity,  and  the  combustion  under 
such  conditions  cannot  be  obtained  entirely  in  the  lower  regions, 
but  some  of  the  air  will  reach  the  upper  regions  unburnt,  where 
it  causes  the  reduction  of  part  of  the  carbonic  acid. 

The  presence  of  free  oxygen  in  the  escaping  gases  of  the 
Herbertz  cupola,  might  lead  to  the  supposition  that  it  has 
a  pernicious  influence  on  the  composition  of  the  iron.  Some 
of  the  elements  in  the  pig  iron,  such  as  carbon,  silicon  and 
manganese,  for  instance,  might  be  oxidized,  and  by  their  partial 
elimination  deteriorate  the  quality  of  the  iron.  Not  only  is  this 
not  the  case,  but  it  seems  that  actual  practice  has  shown  that 
less  carbon  and  silicon  are  eliminated  from  the  iron  in  the 
Herbertz  cupola,  than  in  the  ordinary  blown  cupola.  This  has 
been  explained  in  the  following  manner:  The  combustion  in 
this  cupola  takes  place  a  little  above  the  annular  opening,  and 
no  flame  is  seen  in  the  upper  regions  of  the  cupola,  whereas  in 
the  ordinary  cupola,  combustion  takes  place  through  the  entire 
.length  of  the  shaft  and  continues  in  a  blue  flame  on  top.  In 
this  case  all  the  pig  iron  is  more  or  less  heated  and  pasty  before 
it  reaches  the  melting  zone,  and  surrounded  by  an  oxidizing 
atmosphere,  the  elimination  of  part  of  its  elements  is  easy. 

In  the  Herbertz  cupola,  where  the  combustion  takes  place 
almost  entirely  in  the  lower  regions,  and  where  the  upper  re- 


DIFFERENT   STYLES    OF   CUPOLAS. 

gions  are  less  heated  up,  the  pig  iron  better  resists  the  influence 
of  the  ascending  gases. 

It  must  be  stated  at  once  that  the  above  tests  extended  only 
over  one  single  charge  of  1.5  tons,  lasting  in  the  first  heat  35 
minutes.  Had  the  work  been  continued  for  a  certain  length  of 
time  and  had  a  greater  number  of  charges  been  made,  the  con- 
sumption of  fuel  would  have  been  considerably  lowered,  as  for 
the  following  charge  only  melting  coke  would  have  been  put  in 
the  cupola  without  any  further  addition  of  lighting  coke.  Then, 
if  five  consecutive  charges  had  been  made,  we  should  have  190 
kg.  of  lighting  coke  and  5  X  75,  or  375  kg.  of  melting  coke  (at 
5  per  cent,  of  the  weight  of  iron),  or  a  total  of  565  kg.  And 
as  67  kg.  of  coke  have  been  taken  out  of  the  cupola  after  the 
charge  was  over,  this  would  leave  498,  say  500  kg.  of  coke 
really  burnt,  which  is  equal  to  6.6  per  cent.  In  other  words,  I 
pound  of  coke  would  melt  15.15  pounds  of  iron. 

In  the  cupola  working  for  a  few  weeks  at  Elizabethport, 
the  consumption  of  coke  for  the  melting  proper  amounted 
during  the  tests  to  6  per  cent.  The  cupola  is  rated  as  a  2  ton, 
melting  2  tons  an  hour.  The  outside  diameter  of  the  hearth  is 
4  feet  7  inches,  whereas  the  shaft  has  an  outside  diameter  of 
only  4  feet  4  inches,  and  the  total  height  from  bottom  plate  of 
hearth  to  top  of  cupola  is  13  feet  9  inches,  when  hearth  and 
shaft  are  in  contact  with  each  other.  The  castings  made  during 
the  tests  were  car  wheels,  and  the  mixture  of  iron  put  in  the 
cupola  was  the  same  mixture  of  pig  and  scrap  iron  that  had 
been  used  previously  in  the  old  ordinary  cupola  of  the  foundry, 
viz. :  One-third  No.  I  foundry  iron  and  two-thirds  car-wheel 
scrap.  It  was  melted  down  with  only  6  per  cent,  of  coke,  not 
counting  the  filling  coke.  Notwithstanding  this  very  reduced 
amount  of  fuel,  the  iron  began  to  melt  rapidly.  Ten  to  fifteen 
minutes  after  the  steam  was  put  on  to  create  the  draft,  the  first  iron 
was  tapped  off.  It  was  very  good,  and  so  hot  that  the  men  had 
to  wait  a  few  minutes  before  casting  it  into  the  molds.  Though 
the  iron  mixture  used  in  this  test  was  the  same  as  has  always 
been  made  in  the  old  cupola,  it  must  be  stated  that  the  castings 


180  THE   CUPOLA   FURNACE. 

obtained  were  too  soft  for  car  wheels  and  presented  very  little 
chill  on  the  tire.  In  order  to  obtain  a  better  chill  it  was  deemed 
advisable  to  use  nothing  but  car-wheel  scrap  on  the  second  day. 
The  result  showed  a  marked  improvement  on  the  first  day's 
work ;  the  chill  was  deeper  and  better.  On  the  third  day  the 
mixture  was  one-fourth  No.  3  foundry  iron  and  three-fourths 
average  foundry  scrap.  The  use  of  this  mixture  constituted  a 
large  economy  over  what  had  been  done  in  the  ordinary  cupola, 
and  with  it  better  results  were  obtained  than  with  a  mixture  of 
one-third  No.  I  foundry  and  two-thirds  car-wheel  scrap.  The 
castings  obtained  were  very  tough  and  dense  with  T7g-  inch  chill. 
The  metal,  too  hot  to  be  cast  immediately  after  tapping,  was 
very  pure  throughout  the  cast. 

The  charge  on  this  day  was  as  follows ; 

Filling  coke,  576  pounds. 

Melting  coke,  6X72  =432  pounds. 

Limestone,  6X  15  =90  pounds. 

No.  3  foundry,  6x300=  1800  \  ^  poundg> 

Foundry  scrap,  6x  900  =  5400  J 

The  hearth  in  the  cupola  used  at  Elizabethport  is  mounted 
on  a  small  car.  This  hearth,  prepared  and  dried  outside,  was 
filled  with  wood  shavings,  wood  and  coke  on  top  to  the  upper 
level.  It  was  then  pushed  under  the  shaft,  and  raised  by  means 
of  the  screws  until  it  came  in  contact  with  its  lower  rim.  Fill- 
ing coke  was  then  charged  to  the  level  of  the  highest  bull's-eye, 
and  fire  started  through  the  three  tuyeres  at  the  bottom  of  the 
hearth.  After  this  the  cupola  was  left  to  itself,  working  under 
natural  draft  through  the  three  tuyeres  at  the  bottom.  When 
the  filling  coke  was  fully  ignited  the  above-named  charge  was 
put  on  in  alternate  layers  of  iron,  coke  and  limestone.  When 
the  filling  was  done,  the  hearth  was  lowered  enough  to  form  an 
annular  opening  of  about  I  ^  inches  between  the  lower  rim  of 
the  shaft  and  the  top  of  the  hearth.  The  tuyeres  at  the  bottom 
were  plugged  with  molding  sand,  and  the  cupola  again  allowed 
to  work  with  natural  draft  through  the  annular  opening,  until 


DIFFERENT    STYLES    OF   CUPOLAS.  l8l 

the  first  iron  was  melting  down.  At  this  moment  the  steam-jet 
was  put  in  action.  The  draft,  which,  when  no  steam  was  ap- 
plied, had  been  equal  to  about  y1^  inch  water  column,  rose  at 
once  to  between  3  and  4  inches  of  water.  From  that  moment 
on,  the  melting  was  regular,  hot  and  rapid.  The  top  of  the  cu- 
pola was  kept  tight  and  only  opened  at  regular  intervals  to  in- 
troduce the  raw  materials.  Lighting  coke  was  only  used  at 
the  start;  all  the  subsequent  charges  were  made  with  not  more 
than  6  per  cent,  of  coke,  and  continued  regularly  without  any 
other  addition.  When  the  steam  was  applied,  its  pressure  was 
80  pounds.  The  entire  charge  of  7200  pounds  was  melted  in 
i  hour  and  24  minutes,  which  corresponds  to  5140  pounds  of 
pig  iron  melted  per  hour,  say  2\  tons,  instead  of  2  tons.  The 
vacuum  created  in  the  cupola  remained  between  3  and  4  inches 
of  water  as  long  as  the  level  was  kept  constant.  Toward  the 
end  of  the  charge,  when  this  level  became  lower,  the  vacuum 
fell  somewhat  below  3  inches.  No  disagreeable  noise  was  heard 
while  the  melting  was  going  on,  nor  was  any  spark  or  flame 
seen  at  the  top  of  the  cupola. 

As  soon  as  the- melting  was  done  and  the  last  iron  run  out 
from  the  cupola,  the  bottom  door  of  the  hearth  was  opened  and 
the  ignited  mass  fell  down  into  the  ash  pit,  where,  once  the 
hearth  pulled  out,  the  entire  content  was  cooled  with  water,  and 
the  remaining  coke  gathered  to  be  saved  as  lighting  coke  in  the 
following  melting.  After  careful  weighing  of  the  iron  cast  from 
the  cupola,  it  was  found  that  the  entire  loss  amounted  to  only 
^y2  per  cent.,  a  very  low  figure  when  compared  with  the  ordi- 
nary loss  of  at  least  6  per  cent,  in  an  ordinary  foundry  cupola. 
It  is  remarkable  also  that  a  lower  grade  of  iron  can  be  taken 
and  still  the  same  results  as  in  the  ordinary  cupola  be  obtained. 
Thus  the  tests  at  Elizabethport  have  conclusively  shown  that  as 
good  results  were  obtained  with  a  mixture  of  one-quarter  No.  3 
foundry  iron  and  three-quarters  foundry  scraps  when  melted  in 
the  new  cupola,  as  had  been  obtained  with  a  mixture  of  one- 
third  No.  i  foundry  and  two-thirds  scrap  iron  when  melted  in 
the  ordinary  cupola.  This  may  be  explained  by  the  reason 


1 82  THE   CUPOLA   FURNACE. 

that  less  carbon  and  silicon  are  eliminated  from  the  iron  when 
melted  in  the  Herbertz  cupola. 

HERBEKTZ  CUPOLA  USED  FOR  MELTING  STEEL. 

The  first  tests  made  in  the  Herbertz  cupola  to  melt  steel  were 
attended  with  success.  Rail  ends,  old  files  and  other  iron  or 
steel  crop  ends  were  melted  together  with  a  small  amount  of 
foundry  iron,  and  with  only  3  to  10  per  cent,  of  lighting  coke. 
The  molten  metal  was  liquid  enough  to  be  cast  easily.  How- 
ever, when  small  steel  castings  had  to  be  made  it  was  soon  dis- 
covered that  the  metal  lacked  fluidity,  and  in  order  to  obtain 
better  results,  it  was  deemed  advisable  to  work  with  heated  air. 
Figs.  35  and  36  illustrate  the  construction  of  a  cupola  especially 
adapted  to  this  kind  of  work.  The  cupola  in  all  its  parts  is  en- 
tirely similar  to  the  steam-jet  cupola  used  for  the  melting  of  pig 
iron,  with  the  exception,  however,  that  a  certain  number  of 
wrought-iron  pipes  are  laid  in  the  brick  work.  The  air  enters 
at  the  top  in  a  circular  space,  and  from  there  is  sucked  down  at 
once  through  the  iron  pipes  to  the  lower  part,  where  it  enters 
the  cupola.  By  its  passage  through  the  pipes  it  is  heated  to  a 
temperature  ranging  from  500°  to  1100°  F.  and  consequently 
the  temperature  in  the  melting  zone  will  be  sufficiently  increased 
to  obtain  a  thoroughly  liquid  steel.  Bessemer  steel,  as  well 
as  wrought-iron  crops,  were  melted  in  this  way,  each  separately 
and  with  the  greatest  success. 

For  the  casting  of  heavy  steel  castings  especially,  this  cupola 
is  better  adapted  than  a  crucible.  On  account  of  its  direct  con 
tact  with  the  fuel  at  a  high  temperature,  the  percentage  of 
carbon  in  the  metal  seems  to  slightly  increase.  No  steel-melt- 
ing cupola  is  as  yet  working  in  the  United  States,  but  on  the 
Continent  of  Europe  their  value  seems  to  be  more  and  more 
appreciated. 

For  melting  other  metals  or  alloys,  such  as  lead,  copper, 
brass,  etc.,  the  cupola  has  recently  been  introduced  in  some 
European  works.  Especially  bronze  has  been  melted  in  an 
ordinary  foundry  cupola  with  the  best  results.  The  tempera- 


DIFFERENT   STYLES    OF   CUPOLAS. 
FIG.  35. 


183 


7//////////////////////////////A 

HERBERTZ  STEEL  MELTING  CUPOLA. 


1 84  THE   CUPOLA   FURNACE. 

ture  required  in  this  case  being  lower  than  in  the  case  of  pig 
iron,  the  cupola  worked  with  natural  draft  and  without  any  use 
of  the  steam-jet.  The  fuel  economy  obtained  seems  to  be  very 
large.  The  total  consumption  amounted  to  only  12  per  cent., 
whereas  in  crucibles  this  consumption  is  sometimes  as  high  as 
40  per  cent.  The  fusion,  even  without  the  application  of  the 
steam-jet,  is  claimed  to  be  nearly  five  times  quicker  than  in  the 

FIG.  36. 


crucible  furnace,  and  the  bronze  obtained  is  even  purer  than  the 
bronze  remelted  in  crucibles.  This  is  said  to  be  due  to  the  fact 
that  during  the  fusion,  the  small  amount  of  tin  often  found  in 
bronze  is  burnt  out  and  escapes  in  the  shape  of  a  white  smoke. 
The  loss  of  metal  during  the  melting  seems  to  be  slightly  in- 
creased on  account  of  the  elimination  of  the  tin.  The  cupolas 
used  in  the  remelting  of  these  metals  are  the  same  as  those 
used  for  the  remelting  of  foundry  iron. 

PEVIE  CUPOLA. 

In  Fig.  37  is  seen  the  Pevie  cupola,  designed  by  Mr.  Pevie, 
a  practical  foundryman  of  the  State  of  Maine.  The  small 
cupolas,  1 8  to  24  inches,  of  this  design  are  built  square,  with 
square  corners  in  the  lining,  and  larger  ones  are  made  oblong 
with  square  corners  and  24  to  30  inches  wide  inside  the  lining, 
and  any  increase  in  the  melting  capacity  of  the  cupola  desired, 


DIFFERENT   STYLES    OF   CUPOLAS. 

FIG.  37. 


I85 


PEVIE  CUPOLA. 


I  86  THE   CUPOLA   FURNACE. 

is  obtained  by  increasing  the  length  of  the  cupola  in  place  of 
increasing  the  diameter ;  as  is  done  with  the  round  cupolas. 

Blast  is  supplied  on  two  sides  from  an  inner  air  chamber, 
through  a  vertical  slot  tuyere  extending  the  full  length  of  the 
sides  of  the  cupola. 

The  object  of  Mr.  Pevie  in  constructing  a  cupola  upon  this 
plan  was  to  supply  an  equal  amount  of  blast  to  all  parts  of  the 
stock  and  to  produce  even  melting.  This  theory  was  correct, 
for  blast  was  certainly  more  evenly  distributed  to  the  stock  than 
with  the  small  roynd  tuyere  then  commonly  used,  and  we  saw 
excellent  melting  done  in  cupolas  of  this  construction  in  the 
foundry  of  Mr.  Pevie,  in  a  small  town  in  Maine  (the  name  of 
which  is  forgotten),  which  we  visited  some  twenty  years  since. 
But  in  cupola  construction  an  even  distribution  of  blast  is  not 
the  only  matter  of  importance  to  be  considered  ;  for  if  it  bridges 
and  clogs  up,  the  blast  cannot  do  its  work,  no  matter  how  evenly 
it  may  be  distributed  by  tuyeres  or  by  the  construction  of  a  cu- 
pola, and  the  peculiar  construction  of  this  cupola  made  the  ten- 
dency to  bridge  very  great.  It  was  only  by  careful  management 
that  it  could  in  long  heats  be  prevented  from  bridging,  when 
the  lining  was  kept  in  its  original  shape,  and  for  this  reason  it 
never  came  into  general  use.  We  know  of  only  three  of  them 
at  the  present  time  in  operation,  one  at  Smithville,  N.  J.,  and 
two  at  Corry,  Pa.,  and  the  shape  of  the  linings  in  these  cupolas 
has  been  greatly  altered  from  their  original  form. 

STEWART'S  CUPOLA. 

In  Fig.  38  is  seen  a  sectional  view  of  a  cupola  in  use  at 
the  Stewart  Iron  Works,  Glasgow,  Scotland.  This  cupola, 
which  is  one  of  large  diameter,  is  boshed  to  throw  the  blast 
more  to  the  center  of  the  stock  and  reduce  the  amount  of  fuel 
required  for  a  bed.  Blast  is  supplied  from  a  belt  air-chamber 
extending  around  the  cupola,  through  a  row  of  tuyeres  passing 
horizontally  through  the  lining  and  a  second  row  placed  above 
and  between  the  tuyers  of  the  first  row  and  pointing  downwards, 
as  shown  in  the  illustration.  The  object  of  this  second  row  of 


DIFFERENT    STYLES    OF    CUPOLAS. 
FIG.  38. 


I87 


STEWART'S  CUPOLA. 


1 88  THE   CUPOLA    FURNACE. 

tuyeres  is  to  increase  the  depth  of  the  melting  zone  and  increase 
the  melting  capacity  of  the  cupola  per  hour.  Attached  to  the 
top  of  the  air-chamber  at  intervals  of  about  two  feet,  is  placed 
a  vertical  gas-pipe  of  two  inches  diameter,  and  from  this  pipe 
four  branches  of  one-inch  pipe  lead  into  the  cupola,  about 
twelve  inches  apart.  The  object  of  these  pipes  is  to  supply  a 
sufficient  amount  of  oxygen  to  the  cupola  above  the  melting 
zone  to  consume  the  escaping  unconsumed  gas,  namely  car- 
bonic oxide  (CO),  above  the  melting  zone,  and  utilize  it  in 
heating  and  preparing  the  iron  for  melting  before  entering  the 
zone.  The  cupola  melts  very  rapidly,  and  is  said  to  be  the 
best  melting  one  in  Glasgow.  But  it  is  very  doubtful  if  the  one- 
inch  gas-pipe  tuyeres  contribute  anything  toward .  the  rapid 
melting,  for  it  is  absurd  to  suppose  that  one-inch  openings 
placed  twelve  inches  apart  vertically  and  two  or  more  feet 
apart  around  the  cupola,  would  supply  a  sufficient  amount  of 
oxygen  to  fill  a  large  cupola  to  such  an  extent  as  to  ignite 
escaping  carbonic^  oxide  in  the  center  of  the  cupola.  While 
they  might  supply  oxygen  for  combustion  of  carbonic  oxide  near 
the  lining,  we  do  not  think  they  would  admit  a  sufficient  amount 
to  be  of  any  practical  value  in  melting,  even  if  they  admitted  a 
volume  of  blast  equal  to  their  capacity  when  placed  in  the  lin- 
ing. This  they  do  not  do,  for  they  are  frequently  clogged  by 
fuel  or  iron,  filled  with  slag  from  melting  of  the  lining,  and  as  a 
lining  burns  away  the  ends  of  the  pipes  are  heated  and  fre- 
quently collapse  at  the  ends,  and  it  is  almost  impossible  to  keep 
them  open  during  a  heat  or  to  open  many  of  them  after  a  heat 
is  melted.  The  rapid  melting  in  this  cupola  is  probably  due  to 
the  arrangement  of  the  first  and  second  rows  of  tuyeres  and  the 
shape  given  to  the  inside  of  the  cupola,  which  is  excellent  for 
cupolas  of  large  diameter. 

THE  GREINER  PATENT  ECONOMICAL  CUPOLA. 

In  Fig.  39  is  shown  the  Greiner  cupola,  manufactured  by  The 
Greiner  Economical  Cupola  Co.,  Kankakee,  111.,  for  which  the 
following  claims  are  made  : 


DIFFERENT   STYLES   OF   CUPOLAS.  189 

In  placing  the  Greiner  Patent  Economical  Cupola  before  the 
foundrymen  and  steel  manufacturers  in  this  country,  we  have 
the  advantage  of  the  splendid  results  already  obtained  with  this 
cupola  in  Europe,  where  more  than  three  hundred  are  in  daily 
use. 

The  adoption  of  the  Greiner  system  of  melting  iron  there  has 

FIG.  39. 


THE  GREINER  PATENT  ECONOMICAL  CUPOLA. 

met  with  the  most  satisfactory  results.  In  no  case  has  the  sav- 
ing of  fuel  been  less  than  twenty  per  cent.,  and  in  some  instances 
it  has  reached  forty  and  even  fifty  per  cent. 

The  novelty  of  the  invention  consists  in  a  judicious  admission 


190 


THE   CUPOLA   FURNACE. 


of  blast  into  the  upper  zones  of-  a  cupola,  whereby  the  com- 
bustible gases  are  consumed  within  the  cupola  and  the  heat 
utilized  to  preheat  the  descending  charges,  thereby  effecting  a 
saving  in  the  fuel  necessary  to  melt  the  iron  when  it  reaches 
the  melting  zone.  In  order  to  fully  explain  the  principle  of  its 
workings,  we  illustrate  in  Fig.  40  a  cupola  of  the  ordinary 


FIG.  40. 


FIG.  41. 


SECTION  OF  ONE  ROW  TUYERE  CUPOLA. 


SECTION  OF  DOUBLE  ROW  TUYERE  CUPOLA. 


design,  with  a  single  row  of  tuyeres  or  air  inlets,  A  A.  The  in- 
coming air  burns  the  coke  in  front  of  the  tuyeres  to  carbonic 
acid  gas,  a  combination  indicating  perfect  combustion.  As 
this  gas  ascends  through  the  incandescent  coke  above,  most  of 
it  is  converted  into  carbonic  oxide  by  the  absorption  of  an 
equivalent  of  carbon.  The  result  of  the  combustion  is,  there- 
fore, a  gas  mostly  composed  of  carbonic  oxide  (CO),  indicating 
an  imperfect  utilization  of  the  fuel,  as  one  pound  of  carbon 
burned  to  carbonic  acid  (CO2)  will  develop  14,500  heat  units; 
whereas,  the  same  amount  of  carbon  burned  to  carbonic  oxide 
(CO)  will  only  develop  4480  heat  units,  or  less  than  one-third 
of  the  heat  given  by  perfect  combustion. 


DIFFERENT   STYLES    OF   CUPOLAS. 


191 


To  avoid  this  loss  of  heat,  additional  tuyeres  have  been  placed 
at  a  short  distance  bb  (Fig.  41)  above  the  lower  tuyeres  to  in- 
troduce air  to  consume  the  carbonic  oxide  (CO),  but  such 
arrangement  does  not  have  the  desired  effect,  because  the 
material  at  that  place  in  the  cupola  has  a  very  high  tempera- 
ture, consequently  the  entering  air  also  ignites  the  coke,  so 
that  the  action  at  the  lower  tuyeres  is  simply  repeated,  and  car- 
bonic oxide  (CO)  again  formed  at  a  short  distance  above  bb. 
This  led  Mr.  Greiner  to  the  following  conclusions : 
In  every  cupola  there  must  be  a  point  cc,  (Fig.  42)  above 
which  the  descending  materials  have  not  yet  reached  the  tem- 

FIG.  42. 


SECTION  OF  GREINER  CUPOLA 

perature  necessary  for  the  ignition  of  the  solid  fuel,  while  the 
ascending  combustible  gas  is  still  warm  enough  to  ignite  when 
brought  into  contact  with  air.  It  is  clear  that  air,  if  properly 
admitted  above  that  point,  will  cause  the  combustion  of  the 
carbonic  oxide  (CO)  without  igniting  the  coke. 

But  if  all  the  air  necessary  for  the  combustion  of  the  carbonic 


192  THE   CUPOLA    FURNACE. 

oxide  (CO)  be  admitted  at  one  place  or  in  one  horizontal  row 
of  tuyeres,  the  heat  developed  will  very  soon  raise  the  tem- 
perature so  as  to  set  fire  to  the  coke,  producing  loss  of  carbon 
as  before.  Hence  the  upper  blast  must  not  be  introduced  on  a 
horizontal  plane,  but  through  a  number  of  small  tuyeres, 
arranged  (either  in  the  form  of  a  spiral  or  otherwise)  so  as  to 
embrace  the  higher  zones  of  the  cupola,  and  must  be  regulated, 
both  as  to  pressure  and  arrangement  and  dimensions  of  pipes, 
according  to  the  capacity  of  each  particular  cupola. 

The  combustible  gases  are  thus  burned  without  heating  the 
coke  to  incandescence,  and  the  heat  thus  developed  is  utilized 
to  preheat  the  iron  and  the  coke,  so  that  they  reach  the  melting 
zone  at  a  higher  temperature  and  require  less  heat  to  effect  the 
melting. 

Another  point  in  favor  of  the  Greiner  economical  cupola, 
and  which  is  very  important  in  most  foundries  and  steel  works, 
is  that  the  application  of  the  Greiner  system  will  increase  the 
melting  capacity  of  the  cupola,  owing  to  the  more  rapid  melt- 
ing in  the  fusion  zone  and  to  the  additional  room  in  the  cupola 
that  previously  was  occupied  by  the  extra -amount  of  coke  not 
now  required.  Owing  to  the  more  rapid  melting,  a  purer  and 
better  iron  is  obtained. 

As  will  be  understood,  the  number,  size,  position  and  arrange- 
ment of  the  upper  tuyeres  vary  considerably,  according  to  the 
capacity  of  the  cupola  to  which  the  system  is  to  be  applied. 

It  can  be  readily  adapted  to  existing  cupolas,  without  mate- 
rial alteration  being  effected,  while  the  only  additional  fittings 
necessary  generally  consist  of  a  circular  pipe  connected  by 
branches  with  the  main  blast  box  of  the  cupola,  valves  to  regu- 
late the  blast,  and  connecting  pipes  for  the  small  tuyeres. 

COLLIAU  PATENT  HOT  BLAST  CUPOLA. 

In  Figs.  43  and  44.  are  seen  external  and  sectional  views  of 
the  Coiliau  patent  hot  blast  cupola,  designed  by  the  late  Victor 
Colliau,  a  civil  engineer,  who  devoted  a  great  deal  of  time  to 
the  study  of  cupola  construction  and  management.  The  cu- 


DIFFERENT   STYLES    OF   CUPOLAS. 


193 


pola  is  at  the  present  time  extensively  used,  and  has  many  good 
points  in  its  construction.     The  following  history  and  descrip- 


FIG.  43- 


FIG.  41. 


PAXSON  HOT  BLAST  COLLIAU  CUPOLA.         SECTION  OF  PAXSON  HOT  BLAST  COLLIAU 

CUPOLA. 

13 


194  THE   CUPOLA   FURNACE. 

tion  of  the  cupola  and  results  obtained  in  melting  are  furnished 
by  his  son,  Victor  Colliau,  Detroit,  Mich.,  who  is  engaged  in 
the  manufacture  of  it.  v  It  is  also  manufactured  with  some  im- 
provements, shown  in  Figs.  43  and  44,  by  J.  W.  Paxson  &  Co., 
Philadelphia,  Pa.,  as  the  Paxson  Hot  Blast  Calliau  Cupola. 

Some  years  since,  the  cupola  for  melting  iron  was  very  in- 
complete and  ineffectual — the  melting  of  twenty-five  tons  at 
one  heat  and  a  rate  greater  than  three  to  four  tons  per  hour 
was  unknown,  and  a  melting  of  three  to  four  pounds  of  iron 
with  one  pound  of  coke  was  considered  a  very  satisfactory 
result. 

Large  castings  could  not  be  made,  and  it  was  considered  a 
large  foundry  that  melted  five  to  six  tons  per  day,  and  later 
(only  a  few  years  ago),  when  large  and  heavy  castings  became 
necessary,  such  as  anvils,  steamboat  bed-plates,  cannon,  etc., 
requiring  ten,  fifteen,  and  still  later  on,  thirty  tons  at  one  time, 
several  cupolas  were  used  and  were  placed  in  a  row,  lighted  at 
the  same  time,  and  when  the  iron  in  each  was  melted  they  were 
tapped  simultaneously,  the  metal  running  in  a  common  channel 
to  the  mould. 

All  these  old-fashioned  cupolas  consumed  too  much  fuel  in 
consequence  of  imperfect  combustion,  as  was*  evidenced  by  the 
large  quantity  of  gas  burning  at  the  top  of  the  chimney,  which 
should  have  been  utilized  in  the  melting  process ;  and  after  a 
few  tons  had  been  melted  the  cupola  clogged  with  cold  iron 
and  slag  and  had  to  be  stopped. 

I  have,  with  my  new  improved  patented  hot  blast  cupola, 
surmounted  all  these  difficulties,  and  am  now  melting  sixty  to 
one  hundred  and  ten  tons  a  day  in  some  of  them,  at  a  speed  of 
fifteen  to  twenty  tons  per  hour,  and  ten  to  thirteen  pounds  of 
iron  to  the  pound  of  coke. 

I  am  now  building  a  cupola  to  melt  twenty-five  tons  per  hour. 

My  claims  are : 

1st.  That  the  working  of  my  new  improved  hot  blast  cupola 
has  never  been  equaled. 

2d.  A  saving  of  from  25  to  50  per  cent,  of  fuel.     I  have  re- 


DIFFERENT   STYLES    OF   CUPOLAS.  195 

placed  cupolas  which  were  melting  five  pounds  of  iron  with  one 
pound  of  coke  by  one  of  my  cupolas  of  the  same  size,  and  melted 
ten  or  twelve  pounds  of  metal  with  one  of  coke. 

3d.  Great  rapidity  of  fusion.  With  the  same  diameter  inside 
of  lining  of  the  old  model,  I  am  melting  in  my  cupola  double 
the  quantity  of  iron  per  hour. 

4th.  One  very  important  feature  is  the  saving  of  iron  in  the 
melting  process.  In  common  cupolas  thejoss  is  from  6  to  10 
per  cent.,  in  my  new  improved  cupola  5  per  cent,  is  the  maxi- 
mum; the  loss  is  as  low  as  3^  per  cent,  in  large  meltings. 

5th.  The  iron  melted  is  improved  compared  with  the  old 
system,  in  which  the  slow  process  of  melting  exposed  the  iron 
for  too  long  a  time  to  the  action  of  the  blast,  which,  by  its 
oxidizing  influences,  burned  the  carbon  combined  with  the  iron, 
and  thus  lowered  its  grade  and  value. 

6th.  Hot  iron  from  the  beginning  to  the  end  of  the  melting, 
and  increasing  the  rapidity  of  the  fusion  as  the  operation  ad- 
vances— for  instance,  on  a  melting  of  forty-seven  tons  of  iron 
in  a  cupola  forty-eight  inches  in  diameter  inside  the  lining  at 
the  Detroit  Car  Wheel  Works,  Detroit,  the  first  ten  tons  took 
one  hour  and  fifteen  minutes  to  melt ;  the  second  ten  tons  one 
hour  and  ten  minutes;  the  third  ten  tons  one  hour;  the  fourth 
ten  tons  fifty  minutes,  thus  showing  a  decrease  of  time  as  the 
operation  advanced — that  is  to  say,  a  better  working  of  the 
cupola  at  the  end  of  the  operation  than- at  the  commencement. 
This  is  exactly  the  reverse  of  what  generally  occurs  in  other 
cupolas. 

7th.  By  following  my  instructions,  providing  the  quality  of 
coke  and  iron  is  preserved,  the  same  result  will  always  be  ob- 
tained ;  that  is  to  say,  that  with  the  pressure  of  blast  indicated 
in  my  instructions,  it  will  take  exactly  the  same  time  to  melt  a 
given  quantity  of  iron  with  the  same  proportion  of  fuel  to  the 
iron  melted. 

8th.  I  claim  that  my  cupola  is  built  in  the  most  substantial 
and  workmanlike  manner;  that  neither  expense  in  material  or 
labor  is  spared  to  make  it  stronger  and  more  durable  than  any 
cupola  hitherto  constructed. 


196  THE   CUPOLA   FURNACE. 

9th.  There  is  a  metallic  shell  surrounding  the  entire  base, 
forming  an  annular  air-chamber,  which  is  provided  with  an  in- 
let at  the  top,  connected  with  the  blower  or  fan,  by  means  of 
which  cold  air  is  driven  into  the  annular  chamber.  To  compel 
a  circulation  of  this  air  around  the  inside  lining  in  order  to  take 
the  caloric  from  it,  thereby  highly  heating  such  air,  and  to  pre- 
vent the  passage  of  such  air  directly  from  the  inlet  at  the  top 
of  the  air-chamber-to  the  outlets  through  the  tuyeres  into  the 
furnace,  I  provide  a  diaphragm,  the  width  of  which  equals  the 
distance  between  the  wall  of  the  furnace  and  the  outer  shell. 
One  end  of  this  diaphragm  is  secured  just  above  the  inlet  at  the 
top  of  the  air-chamber  and  extends  spirally  and  downwardly, 
making  at  least  one  entire  turn  around  the  furnace  and  termi- 
nating at  a  point  just  above  the  tuyeres  and  immediately  below 
the  said  inlet.  This  circulation,  forced  by  the  blower  and  com- 
pelled to  take  its  course  around  the  furnace,  cools  the  latter, 
while  the  air  becomes  heated  on  reaching  the  tuyeres,  through 
which  it  finds  an  outlet,  thus  performing  the  double  function  of 
cooling  the  furnace  and  supplying  a  hot  blast. 

THE  WHITING  CUPOLA. 

In  Fig.  45  is  seen  the  Whiting  patented  cupola,  designed  by 
Mr.  Whiting,  a  practical  foundryman,  and  manufactured  by 
the  Whiting  Foundry  Equipment  Co.,  Chicago,  111.,  of  which 
the  following  description  is  given  by  them : 

The  universal  satisfaction  given  by  the  Whiting  cupola  is 
largely  due  to  the  patented  arrangement  and  construction  of 
the  tuyere  system,  which  is  so  designed  as  to  distribute  the 
blast  most  efficiently,  carrying  it  to  those  portions  of  the  cupola 
where  it  will  do  the  most  good,  under  a  reduced  pressure,  and 
through  an  increased  area. 

There  are  two  rows  of  tuyeres.  The  lower  ones  are  arranged 
to  form  an  annular  air  inlet,  distributing  the  blast  continuously 
around  the  entire  circumference  of  the  cupola. 

This  system  of  tuyeres  is  also  arranged  to  be  adjusted  ver- 
tically. This  provides  for  adjustment  to  the  class  of  work, 


DIFFERENT   STYLES    OF   CUPOLAS. 


197 


kind  of  fuel,  and  changes  in  the  inside  diameter  of  the  cupola. 
These  tuyeres  are  flaring  in  shape  and  admit  the  blast  through 
a  small  area  which  is  expanded  into  a  large  horizontal  opening 
on  the  inside  of  the  cupola,  thus  permitting  the  air  to  reach  the 
fuel  through  an  area  nearly  double  that  through  which  it  enters 


FIG.  45. 


ELEVATION. 


SECTION. 

(SECTIONAL  VIEW  OF  BODY.) 

SECTION  OF  WHITING  CUPOLA. 


the  tuyeres — admitting  the  same  volume  of  blast,  but  softening 
its  force. 

There  is  an  upper  row  of  tuyeres  of  similar  construction  to 
supply  sufficient  air  to  utilize  to  the  fullest  extent  the  escaping 
carbon  gas.  These  tuyeres  are  of  great  service  in  melting  and 


198  THE   CUPOLA   FURNACE. 

in  large  heats — for  small  heats  they  may  be  closed  by  means  of 
our  improved  tuyere  dampers. 

Fig.  45  represents  the  latest  type  of  the  Whiting  patent 
cupola.  A  half  vertical  section  is  represented,  showing  the 
arrangement  of  the  improved  tuyeres  and  the  method  of  adjust- 
ing them  vertically.  These  tuyeres  are  arranged  on  slides  and 
can  be  placed  at  various  heights,  as  shown  by  dotted  lines. 

It  sometimes  happens  that  the  operator  finds  the  cupola  too 
large  for  his  needs.  When  this  is  the  case,  a  thicker  lining  can 
be  used  and  the  tuyeres  adjusted  accordingly,  and  for  small 
heats  the  proper  ratio  of  coke  to  iron  can  be  maintained  ;  other- 
wise a  large  cupola  running  small  heats  will  decrease  this  ratio 
materially,  adding  considerably  to  the  cost  of  castings. 

A  change  can  be  made  from  coke  to  coal  fuel,  and  the  bed 
made  of  suitable  depth,  by  simply  adjusting  these  tuyeres. 

No  other  cupola  has  this  device.  It  practically  gives  the 
operator  two  cupolas  in  one. 

This  figure  also  shows  the  safety  alarm  attachment,  side 
plates,  improved  blast  meter  and  upper  tuyere  dampers,  etc. 

Every  cupola  is  provided  with  the  foregoing  improvements, 
together  with  foundation  plate,  bottom  plate  and  doors,  columns 
(three  to  five  feet  long),  slag  and  tapping  spouts  and  frames, 
peep  holes  with  fittings,  patent  tuyeres  and  charging  doors  and 
frames.  All  fitted  ready  to  erect. 

JUMBO  CUPOLA. 

In  the  accompanying  illustration,  Fig.  46,  is  shown  a  sectional 
elevation  of  the  large  cupola  known  as  Jumbo,  in  use  in  the 
foundry  at  Abendroth  Bros.,  Port  Chester,  N.  Y.,  to  melt  iron  for 
stove  plate,  sinks,  plumbers'  fittings,  soil  pipe  and  other  light 
castings,  all  requiring  very  hot  fluid  iron.  The  cupola,  which 
was  constructed  for  the  purpose  of  melting  all  the  iron  required 
for  their  large  foundry  in  one  cupola,  is  of  the  following  dimen- 
sions :  diameter  of  shell  at  bottom  to  height  of  24  inches,  7  feet 
6  inches  ;  diameter  in  body  of  cupola,  9  feet ;  taper  from  large  to 
$mall  diameter,  5  feet  6  inches  long;  diameter  of  stack,  6  feet; 


DIFFERENT   STYLES   OF   CUPOLAS.  1 99 

taper  from  cupola  to  stack,  6  feet  long ;  height  from  bottom 
plate  to  bottom  of  taper  to  stack,  20  feet ;  height  to  bottom  of 
charging  doors,  18  feet;  two  charging  doors  placed  in  cupola 
on  opposite  sides.  Wind  box  inside  the  shell  extending  around 
the  cupola,  5  feet  6  inches  by  9  inches  wide.  Height  of  tuyeres, 
first  row,  24  inches ;  second  row,  36  inches ;  third  row,  48 
inches.  Size  of  tuyeres,  first  row,  8x5  inches ;  second  row, 
6  x  4  inches  ;  third  row,  2x2  inches.  Number  of  tuyeres  in 
each  row,  8  ;  total  number  of  tuyeres,  24.  Slag  hole,  17  inches 
above  iron  bottom,  1 1  inches  above  sand  bottom.  Two  tap 
holes.  Lining,  18  inches  thick;  over  air  belt,  9  inches.  Di- 
ameter of  cupola  at  bottom,  inside  the  lining,  4  feet  6  inches. 
Diameter  above  taper,  6  feet.  Cupola  supplied  with  blast  by 
No.  6  Baker  blower. 

It  is  charged  as  indicated  in  the  table  as  follows : 


200 


THE   CUPOLA   FURNACE. 


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DIFFERENT   STYLES    OF   CUPOLAS. 


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Three  hundred  and  fifty  pounds  of  limestone  are  placed  on 
each  charge  of  iron,  except  the  last  charge,  and  the  slag  hole 
opened  after  the  blast  has  been  on  about  three-quarters  of  an 
hour  and  permitted  to  remain  open  during  the  rest  of  the  heat. 

FIG.  46. 


JUMBO  CUPOLA. 


The  sprues,  gates  and  foundry  scrap  are  not  milled  before 
charging,  and  the  large  amount  of  limestone  placed  on  each 
charge  is  required  to  liquefy  the  quantity  of  sand  charged  into 
the  cupola  on  the  scrap,  and  prevent  clogging  and  bridging  of 


202 


THE   CUPOLA   FURNACE. 


the  cupola.  Sixty  tons  of  iron  have  been  melted  in  this  cupola 
in  four  hours  from  the  time  the  blast  was  put  on  until  the 
bottom  was  dropped. 

THE  CRANDALL  IMPROVED  CUPOLA  WITH  JOHNSON  PATENT  CENTER 
BLAST  TUYERE. 

In  Fig.  47  is  shown  the  above-named  cupola  and  tuyere 
manufactured  by  the  Foundry  Outfitting  Co.,  Detroit,  Mich., 
a  description  of  which  is  furnished  by  them  as  follows : 

FIG.  47. 


THE  CRANDALL  IMPROVED  CUPOLA  .WITH  JOHNSON 
PATENT  CENTER  BLAST  TUYERE. 

The  cupola  is  designed  with  a  view  of  getting  a  more  efficient 
action  of  the  blast  than  is  possible  to  attain  with  the  methods 
now  in  general  use.  The  experiments  made  in  this  new  de- 
parture have  finally  led  to  a  very  simple  and  durable  con- 
struction, which  we  place  before  the  foundrymen  and  request 
that  they  make  a  thorough  investigation  of  it.  It  is  a  well- 
known  fact  that  the  matter  of  forcing  blast  to  the  center  of  a 
cupola  and  obtaining  a  complete  combustion  of  fuel  at  that 


DIFFERENT   STYLES    OF   CUPOLAS.  203 

point,  has  been  to  many  a  puzzle,  and  various  means  have  been 
tried  to  accomplish  this  end.  But  it  has  been  found  in  all 
cases,  that  a  large  portion  of  the  blast  when  taken  in  at  a  high 
pressure  through  outside  tuyeres,  in  striking  the  fuel  is  forced 
back  against  the  brick  lining,  cutting  it  out  very  rapidly  just 
above  the  tuyeres  and  then  escaping  up  along  the  brick  wall, 
doing  no  good,  thereby  requiring  a  greater  volume  of  blast  to 
melt  the  same  amount  of  iron  than  is  used  when  the  blast  is 
taken  in  at  the  center  of  the  cupola.  In  the  illustration  (Fig. 
47)  is  clearly  shown  the  general  arrangement. 

The  air,  instead  of  being  forced  into  the  cupola- furnace  from 
the  outside,  is  applied  from  the  inside  by  means  of  a  center 
blast  tuyere  attached  to  the  under  side  of  the  bottom  plate. 
This  tuyere  terminates  at  about  the  same  height  as  outside 
tuyeres,  and  a  continuous  annular  opening  is  formed  for  the 
blast  by  putting  on  a  loose  section  of  pipe  and  spacing  it  apart 
by  means  of  pins  that  can  be  varied  in  height,  so  as  to  get  any 
desired  opening.  On  top  of  this  loose  section  a  cap  is  set;  also 
spaced  apart  from  it  by  means  of  pins,  so  that  a  second  open- 
ing is  formed  for  the  blast  to  enter,  and  by  taking  in  more  air 
at  this  point  the  carbonic  oxide,  which  would  otherwise  go  to 
waste,  is  changed  into  carbonic  acid  gas,  forming  the  whole  in- 
terior into  a  melting  zone,  insuring  complete  combustion.  Both 
the  loose  pipe  section  and  the  cap  can  be  removed  to  have  the 
lining  on  them  repaired.  The  horizontal  part  of  the  center 
blast  pipe  has  an  opening  at  the  elbow  which  enables  it  to 
be  cleaned  out,  in  case  any  obstructions  should  fall  through 
the  tuyere  opening  above.  The  drop  doors  close  over  this 
tuyere  and  can  be  opened  without  in  any  way  deranging  it. 
No  belt  air-chamber  is  required,  as  the  tuyere  may  be  con- 
nected direct  to  the  main  blast  pipe ;  but  in  cases  where  such 
air-chambers  already  exist,  the  center  blast  tuyere  may  be  at- 
tached to  them  without  in  any  way  disarranging  the  blast  pipe. 
We  would  draw  special  attention  to  the  fact  that  but  little  ex- 
pense need  be  incurred  in  making  this  change  outside  of  the 
price  charged  for  the  center  blast  tuyere  and  piping. 


204  THE    CUPOLA    FURNACE. 

Claims  are  made  as  follows  : 
ist.  A  saving  in  brick  lining. 
2d.  A  saving  in  fuel. 

3d.  More  rapid  melting  with  less  volume  of  blast. 
4th.  A  more  uniform  temperature  of   iron  than   can  be  at- 
tained by  the  outside  tuyere. 

BLAKENEY  CUPOLA. 

In  Fig.  48  is  seen  a  sectional  view  of  the  Blakeney  cupola 
furnace,  the  following  history  and  description  of 'which  are  fur- 
nished by  The  M.  Steel  Co.,  Springfield,  Ohio. 

FIG.  48. 


SECTIONAL  VIEW  OF  BLAKENEY  CUPOLA  FURNACE. 

By  the  Blakeney  cupola  furnace,  the  air  is  so  distributed  or 
projected  into  the  furnace  as  to  produce  a  uniform  heat,  giving 
the  iron  a  uniform  strength  for  all  kinds  of  castings.  The  fea- 
tures peculiar  to  it  are  as  follows : 

The  introduction  of  a  combination  of  curved  tuyeres  or  chutes 
placed  upon  the  wall  or  lining  of  the  cupola,  and  forming  a 
part  of  the  wall,  a  proper  distance  from  the  bottom,  and  nearly 


DIFFERENT    STYLES    OF   CUPOLAS.  20$ 

surrounding  the  inner  and  outer  sides  of  the  wall.  The  tuyeres 
are  made  of  cast  iron  and  in  sections  for  convenience  of 
handling.  A  blank  space  is  left  in  the  rear  of  the  cupola  two 
feet  wide,  through  which  the  slag  is  blown,  if  required. 

A  chamber  or  base  extending  around  the  cupola  and  enclos- 
ing the  space  in  which  the  air  is  conducted  to  the  tuyeres.  The 
bottom  of  this  chamber,  made  irregular  in  form,  hollows  at 
suitable  intervals  to  allow  the  metal  to  flow  to  the  escape  open- 
ings, in  case  it  overflows  through  the  tuyeres.  The  openings 
are  closed  with  fusible  plugs  of  lead  or  other  material,  to  be 
melted  out  by  the  molten  metal. 

The  blast  is  conducted  to  this  cupola  through  one  pipe,  and 
striking  the  blank  space  sidewise  in  rear  of  chamber,  passes  all 
around  through  the  curved  tuyeres  into  the  center  of  the  fur- 
nace, the  blast  striking  into  the  cupola  every  seven-eighths  of 
an  inch  horizontal,  and  3^  inches  perpendicular,  or  according 
to  diameter  of  cupola. 

As  a  producer  of  a  uniform  grade  of  iron  for  the  purpose  of 
•casting  car-wheels,  it  is  just  what  is  needed  for  the  different 
grades  of  iron  to  prevent  chill  cracking. 

This  cupola,  with  its  many  superior  advantages,  has  also  rows 
of  shelves  bolted  to  the  shell  four  feet  apart  up  to  the  top  of 
the  charging  door,  so  that  it  will  not  be  necessary  to  tear  out 
any  of  the  lining  except  that  which  is  burned  out.  These  cu- 
polas have  run  eighteen  months  with  heavy  heats  without  being 
relined. 

These  various  cupolas  are  shown  and  described,  not  that  we 
endorse  all  that  is  claimed  for  them,  but  to  give  our  readers 
some  idea  of  what  has  been  done  in  design  and  coustruction  of 
them,  and  what  kinds  may  at  the  present  time  be  obtained  from 
cupola  manufacturers.  We  have  by  no  means  exhausted  the 
different  varieties  at  hand,  but  have  probably  given  sufficient 
examples  to  indicate  the  direction  in  which  inventive  genius  has 
gone,  and  the  objectionable  points  in  construction  which  it  has 
been  their  aim  to  overcome. 


OFTHS 

UNIVERSITY 


CHAPTER  VIII. 

^ 

ART   IN   MELTING. 

THE  melting  of  iron  in  a  cupola  is  an  art  that  is  by  many 
foundrymen  and  foundry  foremen  but  little  understood,  and 
they  never  begin  the  melting  of  a  heat  without  a  dread  that 
something  will  happen  to  prevent  the  iron  being  hot  enough 
for  the  work,  or  that  they  may  not  be  able  to  melt  the  entire 
heat.  In  many  foundries  it  is  almost  an  every-day  occurrence 
to  have  something  happen  in  or  about  the  cupola  to  prevent 
good  melting.  The  sand  bottom  cuts  through,  the  front  blows 
out,  the  tap  hole  cannot  be  opened  without  a  heavy  bar  and 
sledge,  slag  flows  from  the  tap  hole  with  the  iron  and  bungs 
up  the  spout  and  ladles,  iron  and  slag  get  into  the  tuyeres, 
daubing  falls  off  the  lining  and  bungs  up  or  bridges  the  cupola, 
stock  lodges  upon  the  lining  in  settling,  and  only  part  of  the 
heat  can  be  melted.  Iron  melts  so  fast  in  one  part  of  the  heat 
that  it  cannot  be  taken  care  of;  in  another  part  it  melts  so 
slowly  that  a  ladle  cannot  be  rilled  before  the  iron  is  too  dull 
for  the  work ;  or,  iron  is  not  melted  of  an  even  temperature 
throughout  a  heat,  and  has  to  be  watched  in  order  to  get 
hotiron  to  pour  light  work;  the  first  iron  is  dull,  or  the  last  is 
dull,  or  the  whole  heat  is  dull.  Some  of  these  troubles  to  a 
greater  or  less  extent  occur  almost  daily,  and  it  is  a  rare  oc- 
currence in  a  great  many  foundries  that  a  perfectly  satisfactory 
heat  is  melted.  In  foundries  in  which  these  difficulties  occur,, 
the  foundryrnan  or  his  foreman,  or  both,  do  not  understand 
melting.  The  cupola  is  in  charge  of  an  old  professional  melter 
who  always  ran  it  in  this  way,  or  a  foundry  laborer  or  helper 
has  been  selected  for  a  melter  and  given  a  few  instructions  by 
some  one  who  has  seen  a  cupola  prepared  for  a  heat,  or  perhaps 

(206) 


ART   IN   MELTING.  2O/ 

has  melted  a  few  heats.  He  is  instructed  until  he  melts  a  heat 
successfully,  and  then  he  "knows  it  all"  and  is  left  to  himself, 
and  perhaps  he  knows  as  much  as  his  instructor.  If  he  is  a 
practical  man,  he  learns  the  cause  of  all  the  troubles  in  melting 
and  in  time  becomes  a  fair  melter ;  but  at  what  an  expense  to 
his  employer ! 

If  he  is  not  a  practical  man,  he  bungles  along  from  day  to 
day  until  he  gets  disgusted  with  his  job  and  quits,  or  is  dis- 
charged, and  another  man  of  the  same  kind  is  tried,  with  about 
the  same  result,  for  there  is  no  one  about  the  foundry  who 
understands  the  art  of  managing  a  cupola  to  instruct  him,  and 
he  must  learn  it  himself  or  as  a  melter  be  a  failure.  The 
foundryman  or  foreman  of  a  foundry  in  which  this  kind  of  melt- 
ing is  done,  will  tell  you  a  cupola  is  a  very  hard  thing  to  man- 
age, and  it  cannot  be  made  to  melt  evenly  throughout  a  heat 
or  the  same  every  heat.  If  this  were  really  the  case,  foundries 
making  very  light  work,  requiring  hot  fluid  iron,  would  lose  half 
their  castings  every  heat  or  be  compelled  to  pour  large  quanti- 
ties of  iron  into  the  pig  bed  and  wait  for  hot  iron.  But  this  is 
not  the  case  in  stove,  bench  and  other  foundries  making  very 
light  castings.  Heats  of  many  tons  are  melted  every  day,  and 
as  many  pounds  of  iron  are  melted  in  one  minute  as  in  another 
from  the  beginning  to  the  end  of  a  heat,  and  there  is  not  a 
variation  of  fifty  degrees  in  the  temperature  of  the  iron  from  the 
first  to  the  last  tap. 

There  is  no  chance  work  in  nature,  and  there  is  no  chance 
work  in  art  when  the  scientific  principles  are  understood  and 
applied  to  practice,  and  there  is  no  chance  work  in  melting 
iron  in  a  cupola  when  the  cupola  is  scientifically  managed,  and 
there  is  no  furnace  used  for  melting  iron  more  easily  managed 
than  the  cupola  furnace ;  but  it  is  necessary  to  understand  its 
construction  and  mode  of  operation  to  do  good  melting. 

In  the  first  place,  the  cupola  must  be  properly  constructed 
and  of  a  size  suitable  for  the  amount  of  iron  to  be  melted,  and 
the  time  in  which  this  melting  is  to  be  done.  For  fast  melting, 
a  cupola  of  large  diameter  is  required,  and  for  slow  melting 


208  THE   CUPOLA   FURNACE. 

one  of  small  diameter.  There  are  those  in  use  at  the  present 
time  in  which  sixty  tons  of  iron  are  melted  in  four  hours,  and 
those  in  which  one  ton  of  iron  is  melted  in  four  hours  and  a 
half,  and  each  of  these  cupolas  melts  iron  as  fast  as  it  can  be 
taken  care  of  after  it  is  melted.  The  large  cupola  would  be 
useless  in  one  foundry,  and  the  small  one  in  the  other.  So  it 
follows  that  a  cupola  must  be  so  constructed  as  to  be  suitable 
for  the  melting  that  it  is  desired  to  do. 

To  melt  iron  hot  and  of  an  even  temperature,  the  tuyeres 
must  be  placed  low,  made  of  a  size  to  admit  the  blast  freely  to 
the  cupola  and  arranged  to  distribute  the  blast  evenly  to  the 
fuel,  and  the  latter  must  be  of  a  proper  volume  for  the  size  of 
cupola.  To  utilize  the  greatest  possible  amount  of  heat  from 
the  fuel,  the  charging  door  should  be  placed  high  and  the  cu- 
pola kept  filled  to  the  door  until  the  heat  is  all  in.  When  pre- 
paring a  cupola  for  a  heat,  it  must  be  properly  chipped  out 
and  the  lining  given  the  best  possible  shape  for  melting,  by  the 
application  of  daubing.  The  daubing  material  must  be  of  an 
adhesive  and  refractory  nature,  and  not  put  on  so  thick  that  it 
will  fall  off  when  dried  or  heated.  The  bottom  door  must  be 
put  up  and  supported  by  a  sufficient  number  of  props  to  make 
it  rest  perfectly  solid  against  the  bottom  plate.  The  bottom 
sand  must  be  of  a  quality  that  will  not  burn  or  be  cut  up  by  the 
molten  iron,  and  it  must  be  of  a  temper  that  will  neither  wash 
nor  cause  the  iron  to  boil.  It  must  be  carefully  packed  around 
the  edges  and  rammed  evenly,  and  no  harder  than  the  sand  for 
a  mould,  and  given  a  proper  pitch  to  cause  the  iron  to  flow  to 
the  tap  hole  as  fast  as  melted.  A  front  and  spout  lining  mate- 
rial must  be  selected  or  prepared  that  will  not  cut  or  melt.  And 
the  front  must  be  put  in  solid  with  a  proper  sized  tap  hole, 
and  the  spout  given  the  right  shape  and  pitch.  The  cupola 
having  been  thus  prepared,  it  is  ready  for  melting.  Shavings 
and  wood  are  put  in  for  lighting  the  melting  fuel  or  bed,  and  a 
sufficient  quantity  of  coal  or  coke  is  put  in  to  fill  the  cupola  to 
the  top  of  the  melting  zone  after  it  has  settled.  As  soon  as 
this  fuel  is  well  on  fire  and  the  heavy  smoke  is  burned  off  so 


ART   IN    MELTING.  2OQ 

that  the  top  of  the  bed  can  be  seen,  it  is  leveled  up  with  a  few 
shovelfuls  of  fuel,  and  charges  of  iron  and  fuel  are  put  in  until 
the  cupola  is  filled  to  the  door.  The  weight  of  the  bed  fuel, 
and  charges  of  iron  and  fuel,  must  be  learned  for  each  cupola, 
for  scarcely  any  two  are  charged  exactly  alike. 

It  will  thus  be  seen  that  the  melting  of  iron  in  a  cupola  is 
very  simple.  But  all  these  things  and  many  more  must  be 
learned  and  practiced  to  make  it  so,  and  they  cannot  be  learned 
in  one  or  in  a  dozen  heats.  Slag  and  cinder  adhere  to  the  lin- 
ing at  one  point  to-day  and  at  another  to-morrow,  and  the 
chipping  out  must  be  different.  The  lining  is  burned  away 
more  at  one  point  to-day  than  it  was  yesterday.  A  new  lining 
requires  a  different  shaping  than  an  old  one,  as  a  lining  burns 
out  and  the  diameter  of  the  cupola  increases.  More  fuel  is  re- 
quired for  a  bed,  and  the  weight  of  charges  of  fuel  and  iron 
must  be  increased.  All  brick  are  not  suitable  for  a  cupola  lin- 
ing, and  a  good  brick  may  be  laid  up  in  such  a  way  that  a 
lining  will  not  last  half  so  long  as  it  would  do  if  properly  put 
in.  All  daubing  material  is  not  suitable  for  repairing  the  lin- 
ing of  a  cupola,  and  the  best  daubing  is  worthless  when  not 
properly  applied.  Bottom  sand  when  used  over  and  over  again 
becomes  worthless,  and  all  sands  are  not  suitable  for  a  bottom. 
The  front  may  be  put  in  with  material  that  melts,  and  the  tap 
hole  cannot  be  kept  open  and  free  of  slag;  or  the  front  made 
of  a  shape  that  iron  chills  in  the  tap  hole  between  taps.  The 
spout  lining  material  may  not  be  suitable,  and  may  melt  and 
bung  up  the  spout  with  slag,  or  the  lining  may  be  made  of  a 
shape  that  two  or  three  ladles  are  required  to  catch  the  many 
streams  that  fall  from  it  at  the  same  time. 

To  learn  to  manage  a  cupola  perfectly,  a  close  study  of  all 
the  materials  used  in  melting  and  their  application  to  melting 
are  necessary,  and  months  of  careful  observation  are  required 
to  learn  them,  but  by  an  intelligent  man  they  can  be  learned. 
A  moulder,  when  serving  his  time  as  an  apprentice,  is  seldom 
given  an  opportunity  to  learn  melting,  and  when  he  becomes 
foreman  of  a  foundry  knows  nothing  whatever  about  the  man- 
14 


210  THE   CUPOLA   FURNACE. 

agement  of  a  cupola  and  is  completely  at  the  mercy  of  the 
melter.  The  time  has  passed  in  many  localities  when  the  entire 
force  employed  in  a  foundry  was  subject  to  the  whims  of  a 
melter  and  compelled  to  take  a  day  off  whenever  he  did  not 
see  fit  to  work,  and  a  foreman  who  does  not  fully  understand 
the  management  of  cupolas  is  no  longer  considered  a  com- 
petent man  to  have  charge  of  a  foundry.  It  should  be  the  aim 
of  every  moulder  who  aspires  to  be  a  foreman  or  foundryman 
to  learn  melting,  and  when  he  takes  charge  of  a  foundry  he 
should  at  once  learn  all  the  peculiarities  of  the  cupolas  of  that 
foundry,  and  be  able  to  run  off  a  heat  as  well  as  the  melter,  or 
instruct  the  melter  how  to  do  it.  In  conversing  with  foremen, 
we  have  frequently  remarked  to  them  that  the  foreman  of  a 
foundry  should  be  the  melter,  and  many  of  them  have  replied 
that  they  would  give  up  the  foremanship  before  they  would  do 
the  melting.  To  be  a  melter  does  not  imply  that  the  melter 
should  perform  the  labor  requisite  to  melting,  for  a  melter  may 
direct  the  melting  of  a  heat  without  ever  touching  the  iron  to 
be  melted  or  any  of  the  material  required  to  melt  it.  By  going 
inside  for  a  few  minutes  and  giving  directions  how  it  must  be 
done,  any  intelligent  man  can  be  employed  to  do  the  work, 
and  he  can  be  instructed  from  the  charging  door  how  to  pick 
out  and  daub  a  cupola  or  repair  a  lining.  He  can  be  shown 
how  to  put  up  the  doors  and  support  them  in  place;  how  to 
prepare  daubing,  front  and  spout  material,  select  and  temper 
bottom  sand,  and  instructed  from  the  charging  door  and  front, 
how  to  put  in  a  bottom  front  and  spout  lining ;  how  to  light 
up  and  burn  the  bed,  and  given  a  slate  of  charges  and  direc- 
tions for  putting  them  in  the  cupola.  After  he  has  been  di- 
rected by  a  competent  melter  in  this  way  for  a  few  heats,  it  is 
only  necessary  for  the  melter  or  instructor  to  inspect  his  work 
from  time  to  time,  to  see  that  it  is  properly  done  and  prevent 
the  lining  getting  out  of  shape  or  other  things  occurring,  in 
which  a  new  melter  cannot  be  instructed  in  a  few  days ;  and  his 
work  should  be  inspected  to  prevent  him  getting  into  a  rut,  as 
melters  so  frequently  do  when  left  to  themselves. 


CHAPTER  IX. 

SCALES  AND  THEIR  USE. 

THERE  is  nothing  more  essential  to  the  good  melting  and 
mixing  of  iron,  than  an  accurate  weighing  scale  upon  the 
scaffold  near  the  cupola  charging  door.  The  best  for  this  pur- 
pose are  the  platform  scales  mounted  on  large  wheels,  with  the 
platform  about  two  feet  above  the  floor  or  on  a  level  with  the 
charging  door.  For  foundries  that  make  a  large  quantity  of 
gates,  sprews  and  light  scrap  to  be  remelted,  an  iron  box  made 
of  boiler  plate  and  open  at  one  end  for  shoveling  out  iron  and 
fuel  should  be  placed  upon  the  scales.  A  one  or  two  ton  scale 
is  sufficient  for  charging  almost  any  cupola,  for  the  iron  and 
fuel  are  weighed  in  charges  or  drafts  that  seldom  exceed  this 
weight,  and  when  large  pieces  are  charged  they  are  generally 
weighed  on  the  scales  in  the  yard.  Scales  placed  in  the  floor 
on  the  scaffold  upon  which  barrows  of  iron  and  fuel  are  weighed 
as  they  are  brought  on  the  scaffold,  give  the  weight  of  the 
stock  used,  but  they  are  of  no  value  in  dividing  it  into  charges 
if  the  stock  is  not  charged  direct  from  the  barrows  into  the 
cupola,  which  is  seldom  done. 

The  melting  of  iron  in  a  cupola,  when  reduced  to  an  art,  con- 
sists in  melting  the  greatest  possible  amount  with  a  given 
amount  of  fuel ;  and  this  can  only  be  done  by  first  learning  the 
amount  of  iron  that  can  be  melted  with  each  pound  of  fuel,  and 
placing  that  amount  upon  the  fuel  in  the  cupola  at  the  proper 
place  to  be  melted.  If  all  the  fuel  required  to  melt  ten  or 
twenty  tons  of  iron  were  first  placed  in  a  cupola  and  all  the 
iron  put  upon  it  in  one  lot,  it  would  be  so  high  above  the  melt- 
iug  zone  that  none  of  it  could  be  melted  until  fully  one-half  of 
the  fuel  had  been  burned  away  and  the  iron  permitted  to  settle 

(211) 


212  THE   CUPOLA   FURNACE. 

to  the  melting  zone,  in  which  case  all  the  fuel  consumed  before 
melting  began  would  be  wasted,  and  the  iron  would  not  have  a 
sufficient  amount  of  fuel  to  melt  it. 

For  this  reason  the  fuel  and  iron  are  divided  into  charges  and 
placed  in  a  cupola  in  layers,  each  layer  of  fuel  being  only  suffi- 
cient to  melt  the  layer  of  iron  placed  upon  it,  when  it  descends 
into  the  melting  zone.  If  the  charge  of  fuel  be  too  heavy,  the 
excess  must  be  consumed  before  the  iron  can  be  melted  by  it ; 
and  if  the  charge  of  iron  be  too  heavy,  all  of  it  cannot  be  prop- 
erly melted  with  the  charge  of  fuel.  It  is,  therefore,  necessary 
that  the  layers  of  fuel  and  iron  should  be  of  exactly  proper  pro- 
portions to  do  economical  melting. 

There  are  many  foundrymen  who  do  not  understand  this 
theory  of  melting,  but  think  fuel  placed  in  a  cupola  melts  iron 
no  matter  how  it  is  put  in,  and  trust  to  their  melter  to  guess 
the  weight  of  fuel  consumed  and  iron  melted  in  an  entire  heat. 
Others  have  the  fuel  and  iron  weighed  in  the  yard  or  upon  the 
scales  placed  in  the  floor  of  the  scaffold,  and  permit  the  melter 
to  guess  the  respective  weights  of  fuel  and  iron  in  charging. 
In  the  first  case  an  excess  of  fuel  is  always  consumed,  the 
melting  is  slow  and  the  amount  of  iron  charged  is  often  more 
than  required  to  pour  off  the  work ;  or  it  is  insufficient,  and  more 
iron  has  to  be  charged  after  the  stock  is  low  in  the  cupola,  and 
the  destruction  of  cupola  lining  is  greater  than  if  the  iron  had 
been  charged  at  the  proper  time.  In  the  second  case  the  melt- 
ing is  irregular,  and  the  temperature  of  the  iron  uneven,  even  if 
only  a  proper  amount  of  iron  and  fuel  to  melt  it  is  placed  upon 
the  scaffold,  for  the  melter  cannot  in  charging  divide  it  evenly. 
No  melter  can  guess  the  weight  of  a  promiscuous  lot  of  scrap, 
sprews,  gates,  etc.,  or  accurately  estimate  the  weight  of  pig 
iron  by  counting  the  pigs.  The  counting  of  shovels,  riddles  or 
baskets  of  fuel  in  charging  is  the  greatest  fallacy  of  all ;  for 
riddles  and  baskets  always  hold  more  the  longer  they  are  in 
use,  and  shovels  hold  less.  The  melter  makes  no  allowance  for 
the  increase  in  size  of  riddles  or  baskets,  but  always  puts  in  a 
few  extra  shovelfuls  to  make  up  for  reduced  size  of  the  shovel, 


SCALES   AND   THEIR  USE.  213 

as  it  wears  down.  Even  when  these  articles  are  new,  a  few 
pounds  more  or  less  may  be  put  on,  so  that  it  is  simply  guess- 
work at  best. 

Placing  upon  a  scaffold  old  worn-out  scales  that  are  unfit  for 
use  in  other  parts  of  the  works  and  frequently  only  weigh 
correctly  on  one  side  or  end,  is  a  mistaken  economy  frequently 
practiced  by  foundrymen.  The  weighing  of  cupola  stock  upon 
such  scales  is  only  guess-work,  and  the  saving  in  fuel  and  im- 
provement in  melting  would  soon  pay  the  cost  of  accurate  scales. 


CHAPTER  X. 

THE   CUPOLA   ACCOUNTS. 

IN  all  well  regulated  foundries  a  cupola  account  of  melting 
is  kept  and  an  accurate  record  made  of  each  heat,  and  pre- 
served for  future  reference.  In  this  way,  the  melting  is  re- 
duced to  a  system  and  the  foundryman  knows  what  is  being 
done  in  his  cupola  each  day  and  is  able  to  make  an  estimate 
of  the  cost  of  melting.  These  records  are  also  of  value  in 
showing  the  amount  of  fuel  required  for  a  bed  and  in  charges 
when  the  cupola  is  newly  lined,  and  the  amount  they  should  be 
increased  as  the  lining  burns  out  and  the  cupola  is  enlarged. 
Mixtures  of  various  brands  and  grades  of  iron  are  recorded, 
with  the  result  of  the  mixtures  upon  the  quality  of  castings,  and 
a  great  deal  of  experimental  work  in  melting  and  mixing  of 
irons  is  saved  and  better  results  are  thus  obtained.  The 
manner  of  keeping  these  accounts  varies  in  different  foundries. 
In  some  they  are  kept  very  simply,  showing  only  the  amount 
of  fuel  and  iron  in  each  charge  and  total  fuel  consumed,  iron 
melted,  and  time  required  in  melting.  Others  show  kind  and 
amount  of  fuel  used,  in  bed  and  charges,  and  amount  of  each 
brand  or  quality  of  iron  placed  in  charges,  total  amount 
melted,  time  of  lighting  up,  time  of  charging,  putting  on  blast, 
first  iron  melted,  blast  off,  pressure  of  blast,  etc. 

Others  are  still  more  elaborate,  and  not  only  show  all  the  de- 
tails of  the  cupola  management,  but  also  a  report  presenting 
cost  of  various  castings  produced,  good  and  bad,  the  cost  of 
the  bad  ones  being  charged  to  the  good  ones  made  off  the 
same  pattern  or  for  the  same  order,  and  the  average  found. 

To  give  foundrymen  who  have  never  used  such  reports  an 
idea  of  how  they  are  made  out,  we  here  give  a  few  blank  re- 
ports from  leading  foundries.  That  of  Abendroth  Brothers, 
Port  Chester,  N.  Y.,  and  Byram  &  Co.,  is  filled  in  to  show  the 
manner  of  placing  the  various  items  in  the  blank  report. 

(214) 


THE   CUPOLA   ACCOUNTS. 


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2l6  THE   CUPOLA   FURNACE. 

BYRAM    £   COMPANY, 
IRON  WORKS. 


435  and  437  Guoin  Street. 
46  and  48  Wight  Street. 


DETROIT,  MICH. 
FUEL  USED  and  IRON  MELTED  at  the  Foundry  of 


IN  THE  COLLIAU  CUPOLA 


SIZE 

Bed 

FUEL. 
.....  i  700 

i. 

2. 

3- 
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10. 

11. 

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2000 

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Loading  Commenced,         I 
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15       o'clock. 

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CHARGES. 


REMARKS: 


Dated  at 189. 


No.. 


THE   CUPOLA  ACCOUNTS. 


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218 


THE   CUPOLA   FURNACE. 


:  MELTING  SHEET  OF  SYRACUSE  STOVE  WORKS. 

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THE   CUPOLA   ACCOUNTS. 


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THE  CUPOLA  FURNACE. 

CUPOLA  SLATE  FOR  CHARGING  AND  CUPOLA  REPORT. 


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THE   CUPOLA   ACCOUNTS.  221 

The  blanks  for  these  reports  and  records  of  them  are  fur- 
nished to  the  foundry  foreman  or  melter,  and  preserved  in  dif- 
ferent ways.  In  some  foundries  they  are  furnished  in  separate 
sheets,  and  when  filled  out  and  returned  are  kept  in  files  pro- 
vided for  the  purpose.  In  other  foundries  they  are  made  out 
in  book  form  and  filled  in  by  the  foreman  or  foundry  clerk. 
Such  reports  can  be  kept  by  a  foundry  foreman  when  provided 
with  a  small  office  for  doing  such  work ;  but  when  there  is  no 
office,  as  is  frequently  the  case,  a  report  book  kept  by  the  fore- 
man soon  becomes  so  soiled  that  it  is  useless  for  reference,  and 
report  blanks  are  generally  furnished  in  separate  sheets  and 
either  filed  or  transferred  to  the  report  book  by  the  foundry 
clerk.  When  only  a  record  of  fuel  used  and  iron  melted  is  kept, 
the  report  is  generally  made  on  a  slate  upon  which  lines  are 
scratched  similar  to  those  in  a  printed  report,  and  name  and 
amount  of  various  grades  of  iron  and  fuel  filled  in  with  the 
slate  pencil.  The  fuel  to  be  used  and  amounts  of  various  irons 
to  be  melted  in  each  charge  are  placed  upon  the  slate  by  the 
foreman  and  given  to  the  melter  to  charge  the  cupola  by,  and 
after  the  heat  is  melted  the  slate  is  sent  to  the  foundry  office  to 
be  copied  into  the  cupola  account  book.  This  latter  is  the 
oldest  way  of  making  out  these  reports. 

A  cupola  account  is  of  no  value  if  not  correctly  kept,  and  it 
should  be  the  aim  of  every  foundry  foreman  to  see  that  the  re- 
port he  makes  of  fuel  consumed  and  iron  melted  is  correct,  and 
not,  as  is  frequently  done,  endeavor  to  make  a  good  showing  for 
himself,  of  melting  a  large  per  cent,  of  iron  with  a  small  per 
cent,  of  fuel,  and  permit  his  melter  to  shovel  in  extra  fuel  to 
make  iron  sufficiently  hot  to  run  the  work.  Foundrymen  can 
readily  ascertain  the  amount  of  fuel  consumed  by  comparing 
the  amount  reported  with  the  amount  purchased.  False  reports 
only  reduce  the  foreman  in  the  estimation  of  his  employers, 
and  are  frequently  the  cause  of  his  losing  his  position. 


CHAPTER  XI. 

PIG   MOULD    FOR   OVER   IRON. 

IN  foundries  in  which  the  iron  is  all  poured  from  hand  ladles, 
there  is  frequently  a  small  amount  of  iron  left  in  a  ladle  that  is 
not  sufficient  to  pour  a  mold,  and  cannot  be  used  except  when 
the  iron  is  very  hot  and  the  moulder  catches  in  immediately 
after  pouring. 

Moulders  will  not  take  the  time  to  carry  this  iron  back  to 
the  pig  bed  at  the  cupola,  and  it  is  generally  poured  upon  the 
floor  in  the  gangway  or  into  the  sand  heaps ;  and  a  great  deal 
of  light  scrap  is  in  this  way  made  in  large  foundries,  that  re- 
quires much  time  and  labor  to  collect  and  even  when  carefully 
collected  with  much  loss  in  the  sand  and  gangway  dirt.  To 
obviate  this  wastage  of  iron  and  labor,  many  foundries  have 
FlG-  49-  adopted  the  cast  iron  pig  mould 

shown  in  Fig.  49,  and  placed  one 
of  them  in  the  gangway  at  the 
head  of  each  floor,  or  at  conveni- 
ent distances  apart  in  the  gang- 
PIG  MOULD  FOR  OVER  IRON.  ways  for  the  mOulders.  All  the 

over  iron  is  poured  into  these  moulds  and  is  collected  in  a  pig 
of  convenient  size  for  handling  and  melting,  greatly  reducing 
the  loss  of  iron  and  cost  of  removing. 

(  222  ) 


CHAPTER  XII. 

WHAT  A  CUPOLA  WILL  MELT. 

THE  cupola  furnace  was  originally  designed  for  melting  cast 
iron  for  foundry  castings,  and  at  the  present  time  is  principally 
employed  for  that  purpose,  but  it  is  now  also  used  in  the  melt- 
ing of  almost  all  of  the  various  grades  of  manufactured  iron 
and  steel,  and  many  other  metals. 

It  is  extensively  employed  in  the  melting  of  pig  iron  in  the 
manufacture  of  Bessemer  steel,  and  in  the  melting  of  iron  for 
castings  to  be  converted  into  steel  and  malleable  castings  after 
they  are  cast.  It  is  also  used  in  melting  steel  for  steel  cast- 
ings, but  as  it  makes  an  uncertain  grade  of  steel  is  only  em- 
ployed for  the  more  common  grade  of  castings. 

It  is  also  employed  in  melting  tin  plate  scrap,  sheet  iron, 
wrought  iron  and  steel  wire,  gas  pipe,  bar  iron,  horse  shoes  and 
all  the  various  grades  of  malleable  wrought  and  steel  scrap, 
found  in  a  promiscuous  pile  of  light  scrap  and  used  in  the 
manufacture  of  sash,  elevator  and  other  weights,  and  melts  them 
readily,  producing  a  very  hot  fluid  metal,  and  when  properly 
managed  is  the  very  best  furnace  for  this  purpose. 

It  is  to  some  extent  used  in  the  smelting  of  copper  ores  and 
the  melting  of  copper,  in  the  manufacture  of  brass,  and  also  in 
the  melting  of  brass  for  large  castings ;  but  in  melting  brass, 
the  alloy  is  oxidized  to  so  great  an  extent  that  an  inferior 
quality  of  brass  is  produced  to  that  obtained  from  crucibles. 

Lead  is  frequently  melted  in  cupolas.  It  melts  more  slowly 
than  would  naturally  be  expected,  and  it  is  very  difficult  to  re- 
tain it  in  a  cupola  in  the  molten  state,  as  it  is  almost  impossible 

f  223  ) 


224  THE   CUPOLA   FURNACE. 

to  put  in  a  front  through  which  it  will  not  leak,  and  the  ladle  is 
generally  heated  and  the  tap  hole  left  open. 

The  quantity  of  cast  iron  that  can  be  melted  in  a  cupola  per 
hour  depends  upon  the  diameter  and  height  of  cupola,  and  at 
the  present  time  varies  from  one  hundred  pounds  to  hundreds 
of  tons.  The  number  of  hours  a  cupola  will  melt  iron  freely 
when  properly  managed,  is  only  limited  by  the  length  of  time 
the  lining  will  last.  Cupolas  have  been  run  continuously  from 
one  o'clock  Monday  morning  until  twelve  o'clock  Saturday 
noon,  melting  fourteen  tons  per  hour. 

The  size  and  weight  of  a  piece  of  cast-iron  that  can  be  melted 
in  a  cupola  at  one  heat,  depends  upon  the  size  of  the  cupola. 

As  a  rule,  any  piece  of  iron  that  can  be  properly  charged  in 
a  cupola  can  be  melted.  In  steel-works  cupolas,  ingot  moulds 
weighing  five  tons,  are  melted  with  ease  in  the  regular  charges 
of  the  cupola. 

At  the  foundry  of  the  Pratt  &  Whitney  Co.,  Hartford,  Conn., 
a  large  charging  opening  is  placed  in  the  cupola  for  the  purpose 
of  charging  large  pieces  of  iron  to  be  melted,  and  almost  any 
piece  can  be  melted  in  one  heat  that  can  be  placed  in  the  cupola. 

At  the  foundry  of  the  Lobdell  Car  Wheel  Co.,  Wilmington, 
Del.,  an  oblong  cupola  with  charging  door  placed  at  the  ends 
was  constructed  shortly  after  the  War  of  the  Rebellion  to  melt 
cannon  and  other  heavy  government  scrap,  and  large  cannon 
weighing  many  tons  were  melted  in  this  cupola  without  previ- 
ously breaking  them  up. 


CHAPTER  XIII. 

MELTING  TIN  PLATE  SCRAP  IN  A  CUPOLA. 

TIN  plate  scrap  is  melted  in  the  ordinary  foundry  cupola  the 
same  as  cast  iron  scrap,  but  more  fuel  is  required  to  melt  it. 
The  best  results  are  obtained  with  i  pound  of  coke  to  from  3 
to  4  pounds  of  scrap  and  a  mild  or  light  blast.  Various  ways  of 
preparing  the  scrap  for  charging,  such  as  hammering  or  press- 
ing it  into  ingots  and  forming  it  into  compact  balls,  have  been 
tried ;  but  as  good  results  are  obtained  by  charging  it  in  bulk, 
and  it  is  generally  added  in  this  way.  The  charges  are  made 
of  about  the  same  weight  as  charges  of  iron  in  a  cupola  of 
similar  size,  but  more  fuel  is  added.  The  scrap  when  first  put 
in  the  cupola  is  very  bulky  and  takes  up  a  good  deal  of  room, 
but  when  heated  it  settles  down  into  a  compact  mass,  and  takes 
up  very  little  more  space  than  a  charge  of  cast  iron  scrap. 
Tin  plate  scrap  settles  rapidly,  but  melts  slower  than  cast  iron 
scrap  or  pig. 

Numerous  attempts  have  been  made  to  recover  the  tin  de- 
posited upon  the  iron  by  heating  the  scrap  in  various  ways  to 
a  temperature  at  which  tin  melts,  but  the  coating  of  tin  is  so 
light  it  will  not  flow  from  the  iron.  All  such  attempts  to  re- 
cover it  have  proved  failures.  The  iron,  or  rather  steel,  which 
is  coated  with  tin  is  a  very  soft  and  tough  material,  but  when 
melted  the  tin  alloys  with  it,  and  the  metal  produced  is  very 
hard  and  brittle.  The  molten  metal  from  this  scrap  has  very 
little  life,  chills  rapidly  in  the  spout,  ladles  or  molds,  must  be 
at  a  white  heat  when  drawn  from  the  cupola,  and  must  be 
poured  as  quickly  as  possible.  When  not  melted  extremely 
hot  the  metal  expands  or  swells  in  cooling  to  so  great  an  ex- 
tent as  to  tear  a  sand  mold  to  pieces  or  break  an  iron  mold 
15  (225) 


226  THE   CUPOLA   FURNACE. 

where  it  cannot  escape.  When  the  metal  is  melted  very  hot 
this  expansion  does  not  take  place  to  so  great  an  extent,  and  a 
sand  or  iron  mold  may  be  used  for  any  work  into  which  it  is 
to  be  cast. 

The  molten  metal  is  more  susceptible  to  the  effect  of  mois- 
ture than  iron,  and  is  instantly  thrown  out  of  a  mold  when 
sand  is  worked  too  wet  and  cannot  be  made  to  lay  in  it.  The 
sand,  must,  therefore,  be  worked  as  dry  as  possible.  The  metal 
is  very  hard  and  brittle,  and  only  fit  for  sash  and  other  weights, 
and  even  these  when  light  and  long  must  be  handled  with  care 
to  avoid  breaking.  The  weights  when  rough  cannot  be  chipped 
or  filed  smooth,  and  sash  weights  made  of  this  metal  are  gen- 
erally sold  at  a  less  price  than  iron  weights ;  for  when,  rough 
they  wear  out  very  quickly  the  wooden  box  in  which  they  are 
"hung,  and  builders  dislike  to  use  them.  .  A  foundryman  who 
recently  had  a  contract  from  the  Government  for  a  number  of 
weights  of  several  tons  each,  to  be  used  for  holding  buoys  in 
the  ocean,  made  them  from  tin  plate  scrap.  When  cast  they 
'were  so  rough  that  he  remarked  it  was  a  good  thing  they  were 
to  be  sunk  in  the  mud  under  the  ocean,  for  they  were  not  fit  to 
"be  seen. 

In  a  number  of  experiments  we  made  in  melting  this  scrap, 
we  found  we  could  produce  a  gray  metal  from  it  about  as  hard 
as  No.  3  pig  iron,  by  melting  it  with  a  large  per  cent,  of  fuel 
and  a  very  light  blast.  But  the  metal  was  very  rotten  and  had 
little  if  any  more  strength  than  when  white.  We  tried  a  number 
of  experiments  to  increase  its  strength,  but  in  none  of  them  did 
we  succeed  to  any  extent.  Melting  it  very  hot  and  running  it 
into  pigs  and  remelting  the  pig  improved  the  strength  in  some 
degree ;  but  this  was  expensive,  and  the  results  did  not  justify 
the  expense.  We  also  made  a  number  of  tests  to  learn  the 
amount  of  metal  lost  in  melting  this  scrap,  and  found  with  a 
light  or  proper  amount  of  blast  to  do  good  melting  there  was 
practically  no  loss.  With  a  strong  blast  the  loss  was  heavier, 
and  in  one  heat,  with  a  very  heavy  blast,  we  lost  10  per  cent,  of 
the  metal  charged.  The  metal  from  this  heat  was  a  little 


MELTING  TIN   PLATE   SCRAP   IN   A   CUPOLA.    '  22 7 

stronger  and  also  a  little  harder,  which  was  probably  due  to 
oxidation  of  the  tin  and  iron  by  the  strong  blast  before  melting. 
In  melting  old  roofing  tin,  rusted  scrap  and  old  cans,  the  loss 
in  melting  varied  from  10  to  25  per  cent,,  which  was  probably 
due  to  rust,  paint  and  solder  used  in  putting  the  work  together. 

Tin  acts  as  a  flux  when  melted  with  iron,  and  renders  it  more 
fusible.  Scrap  from  which  the  tin  has  been  removed  by  acids 
to  recover  the  tin  or  fey  the  process  employed  in  the  manu- 
facture of  chloride  of  tin,  is  more  difficult  to  melt  in  a  cupola 
than  when  covered  with  tin,  and  more  fuel  and  time  are  re- 
quired to  melt  it,  but  a  better  grade  of  iron  is  produced  from  it. 
Scrap  of  this  sort  should  be  melted  soon  after  the  tin  is  removed 
from  it,  for  it  rusts  very  quickly,  and  when  rusted  to  any  extent 
produces  nothing  but  slag  when  melted. 

Scrap  sheet  iron  is  more  difficult  to  melt  than  tinned  scrap 
and  is  seldom  melted  in  a  cupola,  for  better  prices  are  paid  for 
it  by  rolling  mills  than  foundrymen  can  afford  to  offer. 

Galvanized  sheet-iron  scrap  cannot  be  melted  at  all  in  a  cu- 
pola in  large  quantities,  for  the  zinc  used  in  galvanizing  it, 
acting  like  the  zinc  solution  used  in  the  Babcock  fire  extin- 
guishers, cools  the  fire  in  the  cupola  to  a  marked  degree.  When 
melting  tinned  scrap  any  galvanized  scrap  that  has  been  mixed 
with  it  must  be  carefully  picked  out,  for  even  in  small  quanti- 
ties it  lowers  the  heat  in  a  cupola  to  such  an  extent  that  the 
metal  from  the  tinned  scrap  cannot  be  used,  and  must  be  poured 
into  the  pig  bed  if  it  runs  from  the  cupola  at  all.  There  are  a 
number  of  ways  of  doctoring  the  metal  from  tin-plate  scrap 
when  it  melts  or  flows  badly,  by  the  use  of  gas  and  oil,  retort 
carbon,  etc.,  but  they  do  not  improve  the  quality  of  the  metal 
to  any  extent,  and  it  is  very  doubtful  if  they  increase  its  melt- 
ing or  flowing  properties. 

A  cupola  of  any  suitable  size  can  be  employed  for  melting 
tin-plate  scrap  and  an  entire  heat  of  the  scrap  may  be  melted 
alone,  or  it  may  be  mixed  with  cast  iron  scrap  or  pig,  and 
melted,  or  again,  it  may  be  melted  alone  directly  after  a  heat 
of  iron.  It  is  a  common  practice  in  many  small  foundries  to 


228  THE   CUPOLA   FURNACE. 

melt  this  scrap  in  the  cupola  for  sash  and  other  weights 
directly  after  melting  a  heat  of  iron  for  soft  castings.  An  extra 
heavy  charge  of  fuel  is  placed  upon  the  last  charge  of  iron  to 
check  the  melting  for  a  few  minutes  by  preventing  the  scrap 
settling  into  the  melting  zone,  and  the  soft  iron  is  all  melted  and 
drawn  off  before  the  scrap  begins  to  come  down.  In  melting 
long  heats  of  this  scrap  it  is  necessary  to  flux  the  cupola  with 
limestone  or  shells  in  sufficient  quantities  to  produce  a  fluid 
slag.  The  flux  should  be  put  in  on  the  first  charge  of  scrap  in 
very  small  cupolas  and  on  the  second  or  third  charge  in  large 
cupolas,  and  on  each  charge  throughout  the  heat  afterward.  The 
slag  hole  should  be  placed  at  the  lowest  point  consistent  with 
the  amount  of  molten  metal  to  be  collected  in  the  cupola  at  one 
time,  and  opened  as  soon  as  the  first  charge  of  scrap,  upon 
which  flux  is  placed,  has  melted.  The  slag  hole  may  be 
opened  and  closed  from  time  to  time,  but  it  is  better  not  to 
make  the  hole  too  large,  and  leave  it  open  throughout  the  heat. 
The  flow  of  slag  then  regulates  itself  and  there  is  no  danger  of 
it  running  into  the  tuyeres.  In  melting  a  few  hundredweight 
of  this  scrap  in  a  cupola,  after  melting  a  small  heat  of  iron,  it 
is  not  necessary  to  charge  flux  in  sufficient  quantities  to  pro- 
duce a  fluid  slag  to  be  tapped,  unless  the  cupola  is  very  small 
and  shows  signs  of  bunging  up.  In  this  case  flux  must  be 
charged  with  the  iron,  and  slag  tapped  early  in  the  heat,  to 
keep  the  cupola  in  condition  to  melt  the  scrap  after  the  iron  is 
melted. 

When  constructing  a  cupola  expressly  for  melting  tin-plate 
scrap  the  charging  door  or  opening  should  be  placed  about  6 
inches  above  the  scaffold  floor,  so  the  scrap  may  be  dumped  in 
from  a  barrow  and  save  handling  it  a  second  time  with  forks. 
The  charging  door  should  be  much  larger  than  in  a  cupola  of 
the  same  diameter  for  melting  iron  and  should  be  not  less  than 
3  or  4  feet  square  in  any  case,  and  for  cupolas  of  very  large  in- 
side diameter  the  opening  should  be  equal  to  one-half  or  three- 
fifths  the  diameter  of  the  shell,  and  4  or  5  feet  high.  The 
height  of  the  door  above  the  bottom  depends  upon  the 


MELTING   TIN   PLATE   SCRAP   IN  A   CUPOLA.  22Q 

diameter  of  the  cupola.  In  large  cupolas  it  should  be  placed 
1 8  or  20  feet  above  the  bottom  and  in  smaller  cupolas  as  high 
as  possible  without  danger  of  the  stock  hanging  up  in  the 
cupola  before  settling  into  the  melting  zone.  The  lining 
material  must  be  carefully  selected,  for  a  poor  fire  brick  will 
not  last  at  the  melting  zone  through  one  long  heat;  in  fact, 
none  of  the  fire  brick  lasts  very  long  at  this  point  and  it  is  gen- 
erally necessary  to  put  in  a  few  new  ones  after  each  heat. 
High  silicon  brick  is  said  to  last  better  than  any  other  brick, 
but  some  of  the  native  stone  linings  which  we  have  described 
last  longer  in  melting  this  scrap  than  any  of  the  fire  brick,  and 
they  are  generally  used  for  lining  cupolas  for  this  work.  The 
cost  of  melting  tin-plate  scrap  in  a  cupola  is  from  $i  to  $2  per 
ton  more  than  the  cost  of  melting  iron.  The  amount  of  profit 
in  melting  this  scrap  for  weights,  &c.,  depends,  like  all  other 
foundry  business,  upon  the  location  and  size  of  the  plant  and 
the  management  of  the  business ;  but  at  the  present  time,  even 
under  favorable  circumstances,  the  profits  are  small. 


CHAPTER  XIV. 

COST   OF   MELTING. 

THERE  is  probably  less  known  about  the  actual  cost  of  melt- 
ing iron  in  cupolas  for  foundry  work  than  about  any  other 
branch  of  the  foundry  business.  But  few  foundrymen  make 
any  attempt  at  keeping  a  cupola  or  melting  account.  Many  of 
those  who  do,  keep  it  in  such  a  way  that  they  not  only  fail  to 
learn  the  cost  of  melting,  but  are  misled  by  the  account  to 
suppose  their  melting  costs  them  a  great  deal  less  per  ton  than 
it  really  does.  In  the  majority  of  foundries  the  melting  is  left 
entirely  in  the  hands  of  the  melter,  who  as  a  rule  has  no  system 
for  doing  the  work,  and  has  no  control  over  his  assistants  or  in- 
terest in  having  them  do  a  fair  day's  work.  In  many  of  the 
foundries  we  visit,  twice  the  number  of  men  are  employed  as 
cupolamen  as  are  employed  in  melting  the  same  amount  of  iron 
in  other  foundries,  where  the  facilities  for  handling  the  stock 
are  almost  the  same,  and  the  expense  of  lining  and  daubing 
material  is  frequently  double  with  one  melter  what  it  is  with 
another  in  the  same  sized  cupola  with  the  same  sized  heats. 

In  many  foundries  the  fuel  is  not  weighed,  but  is  measured 
in  baskets,  or  the  number  of  shovels  counted  and  the  weight 
estimated.  When  the  fuel  is  measured  in  baskets,  the  baskets 
always  stretch  and  enlarge,  and  an  old  basket  frequently  holds 
one-third  more  than  a  new  one;  from  10  to  20  pounds  more 
can  easily  be  piled  on  the  top  of  a  basket  after  it  is  filled. 
Foundrymen  who  charge  their  fuel  by  the  basket  always  use 
more  fuel  than  they  estimate  they  are  using ;  when  the  shovels 
are  counted,  each  shovel  may  be  made  to  weigh  more  than  is 
estimated,  and  a  few  extra  shovelfuls  are  always  thrown  in,  for 
fear  some  were  not  full.  When  too  much  fuel  is  used  in  a  cu- 

(230) 


COST   OF   MELTING.  231 

pola  there  is  not  only  a  wastage  of  fuel,  but  there  is  slow  melt- 
ing, increased  destruction  of  the  lining,  and  an  increased  wear 
and  tear  of  the  blast  machinery.  For  these  reasons  every 
pound  of  fuel  that  goes  into  the  cupola  should  be  accurately 
weighed.  Even  when  the  fuel  is  supposed  to  be  accurately 
weighed,  there  should  be  some  check  on  the  melter,  for  he  will 
shovel  in  extra  fuel  if  not  watched. 

At  a  foundry  we  recently  visited  in  New  Jersey  an  accurate 
account  of  the  melting  had  been  kept  for  a  year ;  at  the  end 
of  the  year  the  president  of  the  company  had  figured  up  the 
amount  of  fuel  consumed  in  the  cupola  and  compared  it  with 
the  amount  purchased,  and  found  they  were  short  260  tons. 
At  another  foundry,  where  the  melter  always  reported  melting 
7  pounds  of  iron  to  I  pound  of  anthracite  coal,  they  ran  short 
300  tons  in  a  year.  This  kind  of  work  should  be  prevented  by 
checking  up  the  melter's  report  and  comparing  it  with  each 
car-load  of  fuel  consumed. 

A  cupola  book  should  be  provided,  with  blank  spaces  for  re- 
cording the  weight  of  coal  or  coke  in  the  bed  and  charges,  and 
the  weight  of  each  brand  of  iron,  No.  1,2  or  3  and  scrap,  show- 
ing the  exact  mixture  of  each  charge  and  heat.  A  note  should 
also  be  made  of  the  quality  of  iron  produced  from  the  mixture. 
Such  a  record  is  of  great  value  in  making  mixtures  and  charg- 
ing a  cupola,  if  it  is  properly  kept 

The  cost  of  melting  per  ton  is  figured  in  a  number  of  differ- 
ent ways,  but  to  be  of  any  practical  value  the  entire  cost  of 
melting  should  be  figured  on  as  follows : 

Interest  on  cost  of  cupola  plant  and  depreciation  in  value  of 
same. 

Fire  brick  for  relining  and  repairs. 

Fire  clay,  loam  and  sand  for  cupola  and  ladles. 

Repairs  to  cupola,  blast  pipe,  elevator,  scaffold,  runway, 
blower,  &c. 

Belts,  oil,  &c.,  for  blower. 

One-fourth  the  entire  cost  of  engine. 

Tools,  wheelbarrows,  buckets,  hose,  shovels,  forks,  rakes, 
hoes,  sledges,  picks,  bars,  trowels,  bod  sticks,  tap  bars,  &c. 


232  THE   CUPOLA   FURNACE, 

Wood  for  lighting  up  and  drying  ladles. 

Coal  or  coke  consumed  in  melting. 

Labor  employed  in  removing  the  dump,  making  up  cupola, 
milling  dump  and  gates,  collecting  gates,  scrap  and  bad  cast- 
ing from  foundry,  placing  iron  and  fuel  on  scaffold,  charging, 
breaking  and  piling  iron  in  yard,  breaking  up  bad  castings, 
daubing  ladles,  &c. 

When  the  cost  of  all  these  items  has  been  learned,  and  the 
amount  divided  by  the  number  of  tons  melted,  it  will  be  found 
that  the  cost  of  melting  is  about  $2  per  net  ton  of  iron  in  the 
ladles.  In  foundries  with  all  the  modern  improvements  for 
handling  the  stock  the  cost  is  a  little  less  than  $2  per  ton,  and 
in  foundries  with  none  of  the  improvements  for  handling  the 
stock  and  no  system  in  melting,  the  cost  per  ton  is  as  high  as 
$3.  When  there  is  doubt  as  to  the  accuracy  of  weights  in 
charging,  the  weights  should  be  compared  with  the  fuel  pur- 
chased and  castings  sold,  and  the  cost  of  melting  may  be 
figured  on  the  weight  of  castings  sold  in  the  place  of  the 
amount  of  iron  melted.  To  make  a  cupola  report  of  value,  the 
fuel,  labor  and  tool  accounts  should  be  kept  separate,  and  an 
effort  made  to  reduce  the  expense  of  each  account. 


CHAPTER  XV. 

EXAMPLES  OF  BAD  MELTING. 

MUCH  has  been  written  and  published  on  melting  by  foundry- 
men  and  foundry  foremen,  who  invariably  give  an  account  of 
rapid  or  economical  melting  done  in  their  foundries ;  and  it  is 
seldom,  if  ever,  that  they  publish  accounts  of  poor  melting  or 
poor  heats  melted  by  bad  management  of  their  cupolas,  or  in 
their  attempts  to  reach  that  perfection  in  melting  of  which  they 
write.  In  giving  points  on  melting  for  the  benefit  of  others,  it 
is  as  essential  that  causes  of  poor  melting  should  be  known 
that  they  may  be  avoided,  as  it  is  that  those  essential  to  good 
melting  should  be  known  that  they  may  be  practiced,  and  we 
therefore  present  a  few  instances  of  poor  melting  that  have 
come  under  our  observation  in  foundries  we  have  visited,  or  in 
which  we  have  been  called  upon  to  render  assistance  to  over- 
come troubles  in  melting  which  were  both  annoying  and 
expensive.  In  these  instances  we  only  give  examples  of 
what  may  occur  in  any  foundry,  and  has  occurred  in  many 
of  them,  where  foundrymen  are  wholly  dependent  on  their 
melters. 

In  1878  we  were  engaged  in  making  some  experiments  in 
melting  with  oil  at  the  stove  foundry  of  Perry  &  Co.,  Sing  Sing, 
N.  Y.,  at  that  time  the  largest  stove  works  in  the  country. 
They  were  melting  from  50  to  60  tons  per  day  in  four  cupolas 
entirely  with  convict  labor,  and  the  results  in  melting  were  very 
unsatisfactory.  Mr.  Andrew  Dickey,  one  of  the  firm  and  man- 
ager of  the  works,  came  to  us  one  day  after  some  very  bad 
heats  and  asked  us  to  take  charge  of  their  cupolas,  set  our  own 
wages,  and  carry  on  our  experiments  at  the  same  time.  We 

(233) 


234  THE   CUPOLA    FURNACE. 

took  charge   of  their  cupolas  the  following  day  and  soon  had 
their  melting  going  along  smoothly,  but  we  did  not  like  the  job, 
and  suggested  to  Mr.  Dickey  that  we  should  teach  a  man  to 
melt  who  could  take  our  place  when  we  were  ready  to  leave, 
and  this  he  consented  to  do.     A  man  was  selected  who  proved 
an  apt  scholar,  and  we  soon  had  him  instructed  in  all  the  details 
of  melting,  and  when  we  left  he  took  full  charge  of  the  cupolas. 
Two  years  later  we  received  a  despatch  from  Perry  &  Co., 
stating  that  they  wished  to  see  us  as  soon  as  possible  at  their 
Sing  Sing  Works.     Upon  our  arrival  there  late  in  the  afternoon, 
Mr.  Dickey  informed  us  they  were  having  trouble  with  all  their 
.cupolas,  and  it  had  been  impossible  of  late  to  get  a  good  heat 
out  of  any  of  them,  and  wished  us  to  see  what  was  the  trouble. 
We  found  the  same  man  in  charge  whom  we  had  two  years  pre- 
viously taught  to   melt,  and   inquired   of  him  what  the  trouble 
was.     He  said  he  did  not  know,  that  he  had  fully  followed  our 
instructions  and  had  no  trouble  in  melting  until  within  the  last 
few  weeks;   during  this    time    the  cupolas    had  been   melting 
very  badly.     He  had  increased  and  decreased  the  fuel   in  the 
bed  and  charges,  increased   it  in  one  part  of  the  heat  and  de- 
creased it  in  another,  varied  the  amount  of  iron  on  the  bed  and 
in  the  charges,  but  had  been  unable  to  locate  the  trouble.    We 
asked  him  to  describe  how  the  cupolas  melted,  and  he  said  they 
melted  the  first  few  tons,  which  was  about  the  first  two  charges, 
fast  and  hot ;  after  that  the  melting  gradually  grew  slower  until 
near  the  end  of  the  heat,  when  melting  almost  ceased ;   the  cu- 
polas were  so  bunged  up  every  heat  that  they  could  scarcely  be 
dumped,  and  it  was  only  after  a  great  deal  of  labor  with  bars 
that  a  hole  could  be  gotten  through,  so  that  they  would  cool  off 
by  the  next  morning.     The  iron  was  of  an  uneven  temperature, 
frequently  too  dull   for  pouring  and  in  some  parts  of  the  heat 
white  hard,  although  nothing  but  soft  iron  had  been  charged. 
He  thought  the  trouble  must  be  in  the  blast — that  old  "  no 
blast"  story  that  foundrymen  hear  so  often,  when  melters  do 
not  know  how  to  manage  a  cupola   and  have  to  lay  the  blame 
on  something.     We  informed  him  that  the  trouble  could  not  be 


EXAMPLES    OF   BAD    MELTING 


235 


FIG.  50. 


n 


SECTIONAL  VIEW  LINING  OUT  OF   SHAPE.      NO.  I. 


236  THE   CUPOLA   FURNACE. 

in  the  blast,  or  the  cupolas  would  not  have  melted  the  first  two 
charges  fast  and  hot ;  that  the  trouble  was  the  stock  logged  in, 
settled  or  settled  unevenly  after  melting  the  first  two  charges, 
which  was  the  cause  of  the  uneven  melting  in  the  latter  part  of 
the  heat,  and  he  must  have  permitted  the  linings  to  get  into  a 
shape  that  produced  this  condition  in  the  cupolas.  He  did  not 
think  this  possible,  for  he  had  followed  our  directions  for  shap- 
ing a  lining,  but  admitted  that  he  frequently  found  pieces  of 
unmelted  pig  and  scrap  in  the  cinder  above  the  tuyeres  when 
chipping  out,  which  confirmed  our  theory,  and  we  looked  no 
further  for  the  cause  of  poor  melting. 

The  following  morning  the  cupolas  were  almost  closed  up 
with  cinder  slag  and  iron,  and  after  a  great  deal  of  labor  in 
breaking  down  and  chipping  out  we  found  the  linings  in  the 
shapes  shown  in  Figs.  50  to  53. 

Cupola  No.  T  had  not  been  lined  for  a  long  time,  and  the  lin- 
ing was  burned  away  until  it  was  very  thin  all  the  way  up. 
This  did  not  prevent  the  cupola  melting,  but  should  have  made 
it  melt  faster ;  for  as  a  cupola  is  enlarged  in  diameter  by  burn- 
ing out  of  the  lining  its  melting  capacity  increases ;  but  in  this 
case  the  melter  had  permitted  the  lining  to  become  hollow 
around  the  cupola  just  above  the  tuyeres.  When  the  stock 
settled,  that  on  the  outer  edges  logged  in  this  hollow,  became 
chilled  and  threw  the  blast  to  the  centre  of  the  cupola.  After 
a  few  tons  had  been  melted  the  chilled  stock  over  the  tuyeres 
increased  rapidly  until  the  melting  was  restricted  to  an  open- 
ing in  the  centre,  which  gradually  closed  up  with  the  fan  blast, 
and  the  longer  the  cupola  was  run  the  slower  it  melted,  until 
melting  ceased  altogether. 

In  No.  2  the  lining  was  not  burned  away  to  so  great  an  ex- 
tent as  in  No.  I,  but  the  melter  had  permitted  it  as  in  No.  I  to 
become  hollow  over  the  tuyeres.  He  had  been  troubled  with 
molten  iron  running  into  the  tuyeres,  and  to  prevent  it  doing 
so  had  built  the  lining  out  from  3  to  4  inches  with  daubing  over 
each  tuyere.  This  cupola  like  the  others  was  60  inches  in  di- 
ameter with  six  oval  tuyeres  each  4  by  12  inches  laid  flat.  Over 


EXAMPLES   OF  BAD   MELTING. 
FIG.  51. 


237 


SECTIONAL  VIEW  LINING   OUT   OF  SHAPE.      NO.  2. 


238  THE   CUPOLA   FURNACE. 

each  of  these  tuyeres  was  a  projecting  hump  3  to  4  inches  thick 
and  1 6  to  18  inches  long;  add  to  the  thickness  of  these  humps  a 
hollow  in  the  lining  of  4  to  6  inches  and  a  shelf  from  8  to  10 
inches  wide  was  formed  over  each  tuyere  upon  which  the  stock 
could  not  help  lodging,  and  could  not  be  melted  after  lodging. 
When  the  cupola  was  first  put  in  blast  it  melted  very  well,  but 
after  the  stock  began  to  lodge  gradually,  melted  more  slowly 
until  it  finally  bunged  up.  The  convict  who  had  charge  of  this 
cupola  informed  me  that  every  day,  when  chipping  out,  he  found 
pieces  of  pig  iron  and  unburned  coke  lodged  over  the  tuyeres, 
and  molten  iron  frequently  ran  into  the  tuyeres  when  melting. 
To  prevent  this,  he  had  gradually  built  the  lining  out  over  the 
tuyeres  (from  day  to  day),  until  the  shape  we  have  described 
was  reached ;  but  it  neither  prevented  the  stock  lodging  nor 
the  molten  iron  flowing  into  the  tuyeres,  but  increased  the 
trouble. 

No.  3  (Fig.  52)  had  recently  been  newly  lined,  and  melted  dif- 
ferently from  the  other  two  cupolas.  It  was  in  a  better  shape  over 
the  tuyeres,  and  the  trouble  in  melting  was  not  caused  by  the 
hanging  up  of  the  stock  from  lodgment  over  the  tuyeres,  but 
by  the  escape  of  blast  around  the  lining.  The  cupola  had  been 
lined  with  9  inch  brick  and  its  diameter  greatly  reduced  by  the 
heavy  lining,  and  as  a  result  the  cupola  melted  more  slowly 
than  with  the  old  lining.  To  make  it  melt  faster,  the  melter 
had  chipped  it  out  very  close  every  day  and  permitted  the 
lining  to  burn  out  to  enlarge  the  cupola  at  the  melting  point. 
This  would  have  improved  the  melting  had  the  belly  in  the 
lining  been  given  a  proper  shape ;  but  no  attempt  had  been 
made  to  shape  it,  and  the  lining  was  burnt  out  to  a  depth  of 
from  4  to  6  inches  with  a  sudden  offset  from  the  small  to  the 
large  diameter.  The  stock  did  not  expand  in  settling  to  fill 
this  sudden  enlargement,  and  a  large  part  of  the  blast  escaped 
into  the  belly  and  re-entered  the  stock  above  the  melting  zone. 
This  naturally  threw  the  heat  against  the  lining  at  the  top  of 
the  belly  and  cut  it  out  very  rapidly,  and  would  have  ruined 
the  lining  in  a  week's  time  had  the  cupola  been  permitted  to 


EXAMPLES    OF   BAD   MELTING. 
FIG.  52. 


239 


SECTIONAL  VIEW  LINING  OUT  OF   SHAPE.      NO.  3. 


240  THE   CUPOLA   FURNACE. 

'continue  to  work  in  this  way.  The  belly  in  the  lining  was  filled 
with  stock  when  charging,  and  the  melting  was  very  good  until 
the  stock  settled  and  the  blast  began  to  escape  in  the  manner 
described,  when  it  rapidly  grew  slower  until  it  stopped  alto- 
gether, and  this  cupola  which  had  been  relined  to  make  it  melt 
better  was  the  poorest  melting  one  of  the  lot. 

In  Fig.  53  the  lining  had  been  permitted  to  belly  out  over  the 
tuyeres  at  a  very  low  point  and  a  shelf  formed,  upon  which  the 
stock  lodged  by  building  the  lining  out  over  the  tuyeres,  but  the 
humps  over  the  tuyeres  were  not  so  long  as  those  in  Fig.  51, 
and  the  stock  had  settled  between  the  tuyeres  to  a  greater  ex- 
tent than  over  them.  This  uneven  settling  of  the  stock  had 
thrown  the  heat  against  the  lining  at  different  points  and  burnt 
it  out  in  holes  all  the  way  up  to  the  charging  door. 

Here  were  four  cupolas,  all  of  the  same  diameter,  having  the 
same  number  of  tuyeres,  with  the  lining  of  each  one  in  a  dif- 
ferent shape,  but  all  having  the  same  objectionable  feature — a 
hollow  in  the  lining  over  the  tuyeres,  which  was  the  real  cause 
of  bad  melting.  We  had  all  the  humps  over  the  tuyeres  chipped 
off  and  the  linings  daubed  up  perfectly  straight  for  six  inches 
above  the  tpp  of  the  tuyeres,  all  around  the  cupola,  and  filled 
in  the  lining  above  with  split  brick  and  daubing,  giving  each 
cupola  the  shape  indicated  by  the  dotted  lines.  The  cupolas 
were  then  charged  as  they  were  before  the  trouble  began,  and 
each  one  melted  hot,  even  iron,  throughout  the  heat  and  dumped 
clean.  As  soon  as  the  man  we  had  taught  to  melt  saw  us  shape 
up  a  small  section  of  the  lining,  he  said  :  "  Why,  you  told  me  to 
keep  the  linings  in  that  shape  and  showed  me  how  to  do  it  two 
years  ago."  We  said  :  "  Why  did  you  not  do  it?"  He  said  he 
had  forgotten  it,  and  when  the  cupolas  began  to  work  badly, 
did  not  know  what  to  do,  and  in  fact  had  lost  his  head  and  let 
every  melter  under  him  do  as  they  thought  best.  This  is  fre- 
quently the  case  with  good  melters.  They  forget  points  that 
they  have  learned  in  melting,  have  no  literature  upon  the  subject 
from  which  to  refresh  their  memories,  or  melters  to  consult  who 
are  competent  to  advise,  and  gradually  drift  into  a  routine  of 


EXAMPLES    OF   BAD    MELTING. 
FIG.  53. 


241 


16 


SECTIONAL  VIEW  OF  LINING  OUT  OF  SHAPE.      NO.  4. 


242  THE   CUPOLA    FURNACE. 

work,  and  when  anything  goes  wrong  with  the  melting  do  not 
know  how  to  overcome  the  difficulty. 

BAD  MELTING  AT  A  WEST  TROY  STOVE  WORKS. 

In  1882,  we  visited  the  foundry  of  Daniel  E.  Paris  &  Co., 
West  Troy,  N.  Y.,  and  while  waiting  for  Mr.  Paris,  looked  over 
the  cupola.  We  found  the  lining  in  a  condition  indicating  very 
poor  melting  and  knew  they  were  having  some  trouble  with 
their  iron.  When  Mr.  Paris  returned  and  learned  who  we  were, 
he  informed  us  that  their  foundry  had  recently  burned  down  and 
they  had  moved  into  the  present  one,  which  had  for  some  time 
before  been  idle.  The  boiler  and  engine  were  small  and  they 
were  having  some  trouble  in  melting  for  want  of  power  to  drive 
a  Sturtevant  blower,  which  when  run  at  a  proper  speed  was 
large  enough  for  the  cupola.  They  were  also  endeavoring  to 
melt  up  a  lot  of  scrap  from  their  recent  fire,  and  had  also  pro- 
cured some  of  the  best  brands  of  No.  I  Pennsylvania  irons  and 
Scotch  pig  to  melt  with  it,  but  were  having  some  hard  cast- 
ings. He  wished  to  know  if  we  could  suggest  anything  to  help 
them  out  until  they  could  put  in  a  new  engine  and  boiler,  and 
find  some  softer  pig  iron  to  work  up  the  scraps,  and  he  took  us 
out  to  look  over  the  works  to  see  what  change  could  be  sug- 
gested. 

We  looked  over  the  blower  and  machinery,  which  were  only 
those  employed  in  stove  mounting,  and  then  went  into  the 
engine  and  boiler  room,  where  we  found  a  good-sized  engine 
and  boiler  and  decided  that  they  were  large  enough  to  run  the 
blower  and  all  the  machinery  in  the  works  at  the  same  time. 
The  engineer  at  once  informed  us  that  they  were  too  small  and 
he  could  not  run  any  of  the  mounting  machinery  when  the  blast 
was  on,  or  pump  water  into  the  boiler,  without  reducing  the 
speed  of  the  blower,  and  he  had  to  fill  the  boiler  and  stop  the 
engine  for  half  an  hour  before  putting  on  the  blast  to  get  up 
steam.  We  then  went  into  the  foundry,  where  we  found  a  well 
arranged  cupola  of  fifty-four  inches  diameter  inside  the  lining, 
and  learned  that  they  were  melting  about  eight  tons  of  iron 


EXAMPLES    OF    BAD    MELTING.  243 

each  heat ;  that  from  four  to  four  and  a  half  hours  were  re- 
quired to  run  off  the  heat,  and  they  were  melting  seven  pounds 
of  iron  to  the  pound  of  anthracite  coal.  The  iron  melted  so 
slowly  that  it  was  difficult  to  catch  four  hand-ladles  full  to 
pour  off  a  four  up  before  the  first  ladle-full  was  too  dull  to  run 
the  work,  and  the  iron  was  sometimes  so  hard  that  the  plate 
cracked  when  taken  out  of  the  sand  or  when  knocking  off  the 
gates. 

We  then  went  upon  the  scaffold,  where  we  found  the  coal 
when  charged  was  not  weighed,  but  measured  in  a  basket  and 
dumped  from  the  basket  into  the  cupola.  We  afterwards 
weighed  a  basket  of  coal  filled  as  the  melter  generally  filled  it, 
and  found  it  weighed  almost  twice  as  much  as  the  melter  stated, 
and  with  the  extra  weight  of  coal  in  the  basket  and  the  extra 
shovelfuls  the  melter  said  he  threw  in  to  fill  up  holes,  we  con- 
cluded that  they  were  melting  about  three  pounds  of  iron  with 
one  of  coal,  in  place  of  seven  to  one  as  claimed  by  the  melter. 
No  slate  was  used  in  charging,  sprews  and  gates  were  not 
weighed,  but  the  weight  estimated  by  counting  the  shovelfuls, 
and  pig  was  weighed  by  counting  the  pieces,  estimating  four 
pieces  to  the  hundred  weight.  The  greater  part  of  the  coal, 
when  dumped  into  the  cupola  from  the  basket,  fell  directly 
under  the  charging  door,  where  it  remained ;  and  the  greater 
part  of  the  iron  naturally  went  to  the  opposite  side  of  the 
cupola,  and  this  uneven  charging  naturally  produced  uneven 
melting. 

We  pointed  out  to  Mr.  Paris  that  his  cupola  lining  was  not 
glazed  in  front  of  the  charging  door,  but  was  rough  and  jagged, 
as  linings  generally  are  in  cupola  stacks,  which  is  an  indica- 
tion that  too  great  a  quantity  of  fuel  is  being  consumed  in 
melting  and  that  by  using  less  coal  better  melting  would  be 
done.  He  thought  seven  to  one  was  very  good  melting  and 
knew  none  of  the  foundries  in  Troy  were  doing  any  better,  and 
did  not  think  iron  could  be  melted  sufficiently  hot  for  their  work 
with  a  greater  ratio  of  iron  to  fuel  than  was  being  consumed  in 
their  cupola.  But  he  was  getting  very  poor  results  in  melting, 


244  THE    CUPOLA    FURNACE. 

and  after  considerable  talk  he  concluded  to  let  us  try  a  heat  the 
following  day  with  less  fuel. 

The  following  morning  when  we  went  round  to  have  the  cu- 
pola prepared  for  a  heat,  we  found  the  matter  of  less  fuel  had 
been  talked  over  by  the  entire  foundry  force  and  by  them  con- 
demned. They  argued  that  dull  iron  had  been  melted  with  the 
quantity  of  fuel  used,  and  could  not  be  poured  at  all  if  less  fuel 
were  used.  It  is  a  curious  fact  that  moulders  working  piece 
work  and  losing  work  every  day  from  dull  iron  will  object  to  a 
stranger,  or  any  man  whatever  but  the  melter  making  any 
change  in  the  management  of  the  cupola,  or  as  they  term  it  ex- 
perimenting with  the  cupola.  While  getting  the  cupola  ready 
for  a  heat,  the  moulders  came  to  us  at  the  cupola  or  in  the 
yard,  one  after  another,  and  asked  us  all  kinds  of  questions 
about  melting,  and  Mr.  Paris  came  also  and  asked  us  if  we 
were  sure  we  could  melt  iron  hot  enough  for  their  work  with 
less  fuel  than  they  were  using,  also  if  we  had  ever  done  so 
before ;  and  we  found  that  we  would  have  to  be  very  careful 
what  we  said  or  did,  or  we  would  not  be  permitted  to  run  off 
a  heat. 

The  melter  was  an  old  hand,  who  had  melted  iron  in  a  num- 
ber of  the  foundries  in  Troy  and  was  considered  good.  He 
was  very  much  opposed  to  having  us  do  any  better  melting  in 
the  cupola  than  he  had  done  without  a  new  engine  and  boiler, 
which  he  declared  must  be  put  in  before  anything  better 
could  be  done.  He  knew  all  about  it,  and  to  teach  this  man  to 
melt  with  less  fuel  would  only  be  a  waste  of  time,  for  he  would 
probably  in  less  than  a  week  drift  back  into  the  same  old  rut 
if  not  closely  watched,  and  would  condemn  our  way  of  manag- 
ing a  cupola.  So  we  told  Mr.  Paris  we  could  teach  his  fore- 
man to  melt  in  a  few  days  so  that  he  could  oversee  the  work 
and  teach  a  man  to  do  it  in  case  his  melter  was  sick  or  quit, 
and  that  it  would  be  much  better  for  them  than  for  us  to  show 
their  melter  how  to  work  with  less  fuel.  After  consulting  the 
foreman  it  was  decided  that  we  should  teach  the  foreman,  and 
he  went  on  the  scaffold  with  us.  He  had  the  cupola  made 


EXAMPLES    OF   BAD    MELTING.  245 

up  as  we  directed,  sent  to  a  store  and  purchased  a  new  slate 
and  arranged  a  system  of  mixing  and  charging  the  iron  so 
that  it  would  produce  an  even  grade  when  melted,  having 
had  the  scales  dug  out  of  a  pile  of  rubbish  in  a  corner  and 
cleaned  up,  and  the  iron  and  fuel  placed  conveniently  for 
charging. 

After  everything  had  been  arranged  for  the  heat  we  had  a 
little  time  to  spare,  and  made  it  a  point  to  see  some  of  the  lead- 
ing moulders  and  explained  to  them  that  we  had  shaped  the 
lining  so  that  the  cupola  would  melt  faster  and  with  a  little  less 
fuel  than  they  had  been  using,  and  make  hot  iron.  We  also 
saw  the  engineer  and  informed  him  that  we  would  charge  the 
cupola  in  a  way  that  it  would  demand  less  blast,  and  if  he  filled 
his  boiler  and  had  a  good  head  of  steam  on  just  before  putting 
on  the  blast,  he  could  run  all  the  machinery  required  for  mount- 
ing when  the  blast  was  on.  These  explanations  seemed  to 
satisfy  everybody,  and  the  foreman  was  so  enthusiastic  in  learn- 
ing to  melt  that  we  had  no  further  fear  of  being  run  out  of  the 
works,  and  were  looked  upon  as  the  man  who  understood  his 
business  until  the  heat  was  all  charged  into  the  cupola,  when 
the  melter  went  into  the  foundry  and  said  to  the  moulders : 
"  Be  jabers  yees  will  not  pour  off  to-day  boys,  for  that  cupola 
will  not  make  hot  enough  iron  for  yees  with  all  the  coal  I  was 
after  putting  in,  and  that  man  has  left  out  half  of  the  coal  I  put 
up  for  the  heat.  Yees  may  as  well  go  home  and  save  your 
moulds  for  to-morrow's  heat;  for  yees  will  not  run  your  work 
to-day." 

From  that  time  until  the  blast  went  on,  we  were  looked  at 
shyly  by  all  the  moulders  except  two,  vvrho  had  seen  us  melt  in 
other  foundries ;  but  the  foreman  and  these  two  assured  them 
that  we  understood  our  business  and  they  would  have  a  good 
heat,  which  probably  saved  us  from  being  driven  out,  for  there 
was  a  tough  lot  of  stove- moulders  in  Troy  in  those  days,  who 
considered  their  rights  sacred  and  that  no  punishment  was  too 
great  for  any  man  who  encroached  upon  them. 

When  the  blast  was  put  on,  the  moulders  gathered  round  the 


246  THE   CUPOLA   FURNACE. 

cupola  and  watched  every  tap  until  the  iron  came  down  so  hot 
and  fast  that  the  first  turn  could  not  handle  it,  and  the  second 
turn  was  called  up,  and  they  were  all  kept  on  the  run  until  the 
end  of  the  heat.  Getting  iron  so  fast  and  hot  was  something 
the  moulders  had  never  been  used  to  in  that  foundry,  and  a 
number  of  them  wished  to  know  if  we  were  trying  to  kill  them 
all  by  giving  them  the  iron  so  fast.  But  all  were  delighted 
with  getting  hot  iron  to  pour  off  their  work  and  getting  through 
so  early ;  and  as  we  went  along  the  gangways  to  see  how  the 
castings  were  turning  out,  a  number  of  them  asked  us  to  wait 
until  they  were  shaken  out  and  have  a  glass  of  ale  with  them, 
which  was  the  great  drink  of  the  Troy  moulders.  Had  we 
waited  for  them  we  probably  would  not  have  reached  our  hotel 
that  evening,  for  almost  all  of  them  dropped  into  a  nearby 
saloon  after  they  were  through  with  their  day's  work,  and  we 
should  have  been  asked  to  drink  with  every  one  of  them. 

In  this  heat  we  had  used  considerably  more  coal  than  we 
considered  necessary,  as  we  were  not  familiar  with  the  working 
of  the  cupola  and  desired  to  be  on  the  safe  side  and  make  hot 
iron,  even  though  the  melting  was  a  little  slow,  which  was  the 
case.  Two  hours  were  required  for  the  heat,  but  even  this 
length  of  time  was  fully  two  hours  better  than  they  had  been 
doing,  and  all  the  machinery  required  for  mounting  was  run 
during  the  heat  without  stopping  the  engine  for  half  an  hour  to 
get  up  steam  before  putting  on  the  blast. 

On  the  following  day  we  reduced  the  coal  a  little  more,  and 
on  the  third  day  reduced  it  until  we  were  melting  six  and  a  half 
pounds  of  iron  to  one  of  coal,  and  the  heat  was  melted  in  one 
hour  and  thirty  minutes.  This  was  as  fast  as  the  moulders 
could  handle  the  iron ;  and  as  we  did  not  consider  it  safe  to 
melt  iron  for  stove  plate  with  less  fuel,  although  we  could  have 
done  so,  and  they  did  not  desire  it  melted  any  faster,  we  made 
no  further  attempt  to  save  fuel  or  reduce  time  of  melting. 

The  foreman  learned  very  rapidly,  and  at  the  end  of  three 
days  was  fully  competent  to  oversee  the  work,  and  they  had  no 
further  trouble  in  melting  or  with  hard  iron,  and  were  able  to 


EXAMPLES    OF   BAD    MELTING.  247 

melt  up  all  the  scrap  from  their  recent  fire  with  the  brands  of 
pig  iron  they  had  on  hand,  and  it  was  not  found  necessary  to 
put  in  a  larger  engine  and  boiler  to  get  a  sufficient  blast,  after 
they  had  learned  how  to  manage  the  cupola. 

The  cause  of  bad  melting  in  this  foundry  was  plainly  indi- 
cated to  an  experienced  melter  at  first  glance  by  the  lining 
in  front  of  and  around  the  charging  door,  namely,  too  great 
a  quantity  of  fuel  in  the  cupola  and  too  small  a  volume  of  blast 
for  that  fuel.  So  large  a  quantity  of  fuel  was  charged  for  a  bed 
that  the  iron  placed  upon  it  did  not  come  within  the  melting 
zone,  and  could  not  be  melted  until  the  surplus  fuel  burned 
away  and  permitted  it  to  settle  into  the  zone.  Each  charge  of 
fuel  to  replenish  the  bed  was  too  heavy,  and  the  greater  part  of 
it  had  to  be  consumed  before  the  iron  placed  upon  it  was  per- 
mitted to  enter  the  melting  zone,  and  the  slow  melting  was  due 
to  the  time  required  in  consuming  the  surplus  fuel  before  the 
melting  could  take  place.  The  hard  iron  in  parts  of  the  heat 
was  due  to  uneven  charging,  which  permitted  the  scrap  at  times 
to  be  melted  by  itself  and  drawn  from  the  cupola  without  being 
mixed  with  melted  pig,  and  the  entire  mass  of  iron  was 
hardened  by  being  subjected  for  a  long  time  to  a  high  degree 
of  heat  before  it  was  permitted  to  enter  the  melting  zone  and  be 
melted. 

The  speed  of  the  blower  had  been  increased  to  fully  double 
the  number  of  revolutions  per  minute  given  in  the  directions  for 
running  it,  to  increase  the  volume  of  blast ;  but  the  volume  of 
blast  had  been  decreased  in  place  of  being  increased,  as  was 
supposed  it  had  been  by  the  increase  of  speed,  and  the  cupola 
received  less  blast. 

We  had  no  means  of  definitely  determining  to  what  extent  it 
was  decreased,  but  from  the  appearance  of  the  blast  in  the 
cupola  at  different  stages  of  the  heat,  before  and  after  decreas- 
ing the  speed  of  the  blower,  we  concluded  that  the  volume  of 
blast  was  increased  fully  one-half,  by  running  the  engine  at  its 
normal  speed  and  reducing  the  speed  of  the  blower  to  the 
number  of  revolutions  given  in  the  directions  for  running  it. 


248  THE   CUPOLA    FURNACE. 

This  is  one  of  the  cases  where  the  cupola  air-gauge  in 
common  use  would  have  been  of  value,  for  it  would  have  indi- 
cated a  high  pressure  of  blast  before  the  speed  of  the  engine 
was  increased,  and  located  the  trouble  at  the  cupola  in  place  of 
at  the  engine. 

WARMING  UP  A  CUPOLA. 

In  1 88 1  we  visited  the  plant  of  the  Providence  Locomotive 
Works,  Providence,  R.  I.  The  superintendent,  Mr.  Durgon,we 
believe  was  his  name,  wished  to  know  if  we  were  the  Kirk  that 
wrote  "  The  Founding  of  Metals."  We  informed  him  that  we 
were,  and  he  replied  that  we  might  know  all  about  a  cupola,  but 
our  directions  there  given  for  constructing  a  cupola  were  no 
good,  for  he  had  constructed  a  cupola  on  that  plan  and  it  was  a 
complete  failure.  It  would  not  make  hot  iron,  or  melt  half  the 
amount  per  hour  stated,  or  melt  the  heat  before  bridging  over 
and  bunging  up.  We  informed  him  that  if  he  had  constructed 
the  cupola  exactly  on  the  plan  given  it  would  do  the  work 
stated  it  would  do.  He  invited  us  to  go  into  the  foundry  and 
look  the  cupola  over,  and  if  it  was  not  right  he  would  make  it 
right.  We  accepted  the  invitation  and  looked  the  cupola, 
blower  and  pipes  all  over,  and  could  find  no  fault  with  them. 
The  cupola  was  in  blast  at  the  time  and  we  watched  it  melt 
for  an  hour,  and  it  certainly  was  a  complete  failure.  The  iron 
from  the  beginning  to  the  end  of  the  heat  was  dull,  the  melt- 
ing slow,  and  the  castings  dirty  and  much  harder  than  they 
should  have  been  with  the  quality  of  iron  melted. 

We  knew  that  the  trouble  lay  in  the  management  of  the 
cupola,  and  decided  to  go  round  the  next  day  and  see  the 
melter  make  it  up  for  a  heat.  This  the  superintendent  de- 
cided to  let  us  do,  although  he  thought  he  had  the  best  melter 
in  New  England  and  the  trouble  could  not  be  in  the  manage- 
ment of  the  cupola.  On  the  following  day  we  were  on  hand 
early  and  found  the  cupola  badly  bridged  and  bunged  up. 
The  melter  soon  had  it  chipped  out  and  daubed  up  in  good 
shape,  and  we  saw  that  the  trouble  was  not  in  the  shape  of  the 
lining.  He  then  put  in  a  very  nice  sand  bottom  from  which 


EXAMPLES    OF   BAD    MELTING.  249 

there  could  be  no  trouble  in  melting.  He  next  put  in  shav- 
ings and  a  large  quantity  of  wood,  which  he  burned  to  dry  the 
daubing.  After  this  had  been  dried  he  added  more  wood  and 
a  good  bed  of  hard  coal  which  he  burned  up  to  warm  the 
cupola  for  melting,  and  he  certainly  did  give  it  a  good  warming, 
for  when  the  doors  were  opened  for  charging  the  lining  was 
heated  to  a  white  heat  from  the  bottom  to  the  stack.  He  then 
added  a  little  more  coal  to  level  up  the  bed,  and  began 
charging. 

As  soon  as  we  saw  the  extent  to  which  the  lining  had  been 
heated  and  the  bed  burned,  we  knew  that  the  cause  of  the  poor 
melting  lay  in  the  bed.  In  warming  the  cupola  up  for  melting, 
the  life  had  all  been  burned  out  of  the  coal  and  but  little  of  it 
left  to  melt  with.  The  cupola  was  filled  with  ashes  below  the 
tuyeres,  and  even  if  iron  was  melted  hot  it  would  be  chilled  in 
its  descent  through  these  ashes  to  the  bottom  of  the  cupola. 
The  fuel  thrown  in  just  before  charging  was  flaked  off,  broken 
and  burned  up  by  the  intense  heat  almost  before  the  iron  could 
be  charged,  and  had  it  not  been  that  an  extra  high  bed  was  put 
in  before  warming  up,  not  a  pound  of  iron  would  have  been 
melted. 

We  had  frequently  seen  beds  burned  too  much,  but  had  never 
seen  one  burned  to  the  extent  of  this  one,  or  a  cupola  heated  so 
hot  before  charging,  and  we  stayed  on  the  scaffold  during  the 
filling  of  the  cupola  with  stock  to  see  if  the  intense  heat  in  the 
cupola  had  any  effect  upon  the  stock  that  would  improve  the 
melting  in  any  way.  The  first  charge  seemed  to  be  heated  to 
a  considerable  extent  by  the  hot  lining  and  bed,  and  prepared 
for  melting.  After  this  charge  was  put  in,  the  cupola  cooled  off 
very  rapidly,  and  before  it  was  filled  there  was  scarcely  any  per- 
ceptible heat  at  the  charging  door,  and  the  stock  could  not 
have  been  heated  to  any  extent  above  the  first  or  second 
charge,  by  warming  of  the  cupola.  When  the  cupola  had  been 
filled  the  blast  was  put  on,  and  the  iron  melted  exactly  as  we 
had  seen  it  do  the  day  before,  dull  and  slow.  The  cupola  had 
been  properly  made  up  ;  plenty  of  fuel  had  been  put  in  to  make 


250  THE   CUPOLA   FURNACE. 

hot  iron  -,  charges  of  fuel  and  iron  were  of  about  the  right  pro- 
portion, and  had  been  properly  placed  in  charging,  and  there 
could  be  no  doubt  that  the  trouble  in  melting  lay  in  the  bed,  as 
before  stated. 

The  following  day  the  superintendant  put  the  melter  on  the 
other  cupola  and  gave  us  full  charge  of  the  one  constructed  on 
our  plan.  We  had  it  made  up  in  about  the  same  way  as  the 
melter  did ;  put  in  our  shavings,  wood  and  all  the  bed,  but  a 
few  shovelfuls  to  level  up  with  before  lighting  up.  After  light- 
ing up  we  waited  until  the  heavy  smoke  was  burned  off  and 
the  fire  began  to  show  through  the  top  of  the  bed.  We  then 
leveled  up  the  bed  and  began  charging.  The  only  change  we 
made  in  charging  was  to  reduce  the  fuel  in  the  bed  about  one 
fourth,  and  that  in  the  charges  a  little.  When  the  blast  was 
put  on  iron  came  down  in  about  ten  minutes,  melted  fast  and 
hot  throughout  the  heat,  and  the  same  amount  of  iron  was 
melted  in  one  half  the  time  it  had  been  the  previous  day. 
This  convinced  the  superintendant  that  the  cupola  was  all 
right,  for  it  did  all  we  claimed  it  would  do  and  a  little  more, 
and  it  convinced  us  that  there  was  nothing  to  be  gained  in 
melting  by  warming  up  a  cupola  before  charging. 

BAD  MELTING,  CAUSED  BY  WOOD  AND  COAL. 

In  one  of  the  leading  novelty  foundries  in  Philadelphia  that  we 
visited  some  years  ago  they  were  employing  two  cupolas,  one  40 
inches  and  the  other  30  inches  inside  diameter,  to  melt  8  tons 
of  iron,  and  it  was  very  difficult  to  melt  that  amount  in  these 
cupolas.  We  knew  that  something  was  wrong  and  went  upon 
the  scaffold  to  look  into  the  cupolas  and  found  the  melter  just 
putting  in  the  wood  for  lighting  up,  He  had  put  in  quite  a 
lot  of  finely  split  wood,  and  had  another  barrow  ready  to  add. 
After  this  was  in,  he  went  down  and  got  three  more  barrows 
of  cord-wood  sawed  in  two  and  added  this  and  then  some  long 
wood,  and  when  he  had  it  all  in,  the  cupola  was  filled  to  the 
bottom  of  the  charging  door.  He  then  filled  the  cupola  with 
coal  to  the  top  of  the  charging  door,  putting  in  the  largest 


EXAMPLES    OF   BAD    MELTING.  251 

lumps  he  could  find.  We  asked  him  why  he  put  in  so  large  a 
quantity  of  wood,  and  he  said  it  was  necessary  to  light  the  coal ; 
and  we  presume  it  was,  for  some  of  the  pieces  of  coal  were  as 
large  as  he  could  lift  and  place  in  the  cupola,  and  it  would  re- 
quire considerable  heat  to  start  a  fire  with  such  large  coal ;  and 
he  said  they  could  not  melt  with  any  smaller  coal.  We  tried 
to  convince  him  that  the  cupola  would  melt  better  with  less 
wood  and  smaller  coal,  but  this  was  impossible,  for  he  was  an 
old  melter  and  knew  all  about  it. 

Either  one  of  these  cupolas  would  have  melted  the  amount 
of  iron  they  were  getting  in  the  two,  and  in  less  time,  had  they 
been  properly  managed ;  but  this  was  not  done  and  the  firm 
afterwards  put  in  two  Colliau  cupolas  to  do  the  work.  The 
cause  of  poor  melting  in  these  cupolas  was  too  great  a  quan- 
tity of  hard  wood,  which  took  a  long  time  to  burn  out  and  in 
burning  out  the  bed  was  burned  to  so  great  an  extent  that  the 
cupola  was  filled  with  wood  ashes  and  coal  ashes  before  melt- 
ing began.  The  large  lumps  of  coal  also  contributed  to  the 
poor  melting  by  making  an  open  fire  through  which  the  blast 
escaped  freely  without  producing  a  hot  fire,  such  as  would  have 
been  produced  by  smaller  coal. 

POOR  MELTING  IN  A  CINCINNATI  CUPOLA. 

In  Fig.  54  is  seen  a  sectional  elevation  showing  the  condition 
of  a  small  cupola  we  saw  in  Cincinnati,  Ohio,  a  few  years  ago. 
This  cupola  would  not  melt,  the  founder  said,  and  could  not  be 
made  to  melt.  He  had  put  in  a  new  fan,  and  now  his  melter 
wanted  a  blower,  and  said  the  cupola  would  not  melt  without  a 
forced  blast.  We  examined  the  cupola,  and  suggested  to  the 
founder  that  he  needed  a  new  melter  worse  than  a  new  blower. 

The  cupola  had  not  for  a  long  time  been  properly  chipped 
out,  and  a  belt  of  cinder  and  slag  varying  in  thickness  from  four 
to  six  inches  had  been  permitted  to  adhere  to  the  lining  around 
the  cupola  above  the  melting  point,  and  another  belt  of  cinder 
and  slag  projected  from  the  lining.  Between  these  two  project- 
ing belts  the  lining  had  burned  away,  making  a  deep  hollow  at 


252  THE    CUPOLA    FURNACE. 

the  melting  point.     Entirely  too  much  fuel  had  been  consumed 

FIG.  54. 


ILLUSTRATION  OF  BAD  MELTING. 


EXAMPLES    OF   BAD    MELTING.  253 

in  melting  or  the  belt  of  cinder  and  slag  could  not  have  formed 
above  the  melting  point. 

We  had  all  the  projecting  humps  chipped  off  and  the  hollows 
filled  in  with  fire-brick  and  daubing,  so  as  to  give  the  lining  an 
even  taper.  The  cupola  was  then  properly  charged,  and  there 
was  no  trouble  in  melting  iron  hot  and  fast. 

UNEVEN  BURNING  OF  THE  BED. 

We  were  once  compelled  to  dump  a  cupola  at  the  foundry  of 
Perry  &  Co.,  from  the  carelessness  of  the  melter  in  placing  the 
shavings  and  wood  in  the  cupola  in  such  a  way  that  they  did 
not  light  up  the  fuel  evenly,  and  in  putting  on  the  blast  when 
the  bed  was  only  burned  up  on  one  side.  We  had  not  noticed 
it,  and  he  thought  the  blast  would  make  it  burn  up  on  the  other 
side.  This  it  did  not  do,  and  after  the  cupola  had  been  in  blast 
a  short  time,  it  had  to  be  dumped. 

The  careless  way  in  which  shavings  and  wood  are  often 
thrown  into  a  cupola  from  the  charging  door,  frequently  causes 
an  uneven  burning  of  the  bed  and  bad  melting.  We  had  a 
number  of  poor  heats  in  our  own  foundry,  due  to  this  kind  of 
carelessness,  before  discovering  the  cause  of  them. 

We  might  relate  many  more  examples  of  poor  melting  in 
various  foundries,  but  these  will  probably  suffice,  as  the  causes 
of  poor  melting  when  a  cupola  is  properly  constructed  will 
generally  be  found  in  the  shape  of  the  lining,  burning  of  the 
bed,  or  quantity  of  fuel  used  in  melting  ;  examples  of  which  are 
here  given. 


CHAPTER  XVI. 

MELTERS. 

THERE  is  no  man  about  a  foundry  for  whom  we  have  more 
respect  than  a  practical  and  scientific  melter.  He  is  generally 
a  self-made  man  and  has  learned  the  art  of  melting  himself.  He 
is  a  man  of  intelligence,  who,  perhaps,  has  been  a  melter's 
helper  and  a  close  observer  of  the  work,  and  when  given  charge 
of  a  cupola,  has  followed  in  his  footsteps  or  improved  on  the 
methods  of  his  predecessors.  He  may  have  been  a  man  who 
was  given  a  few  instructions  in  melting  when  he  first  began,  and 
has  become  an  expert  through  his  own  efforts.  He  is  respected 
by  the  foreman  and  moulders,  and  well-paid  by  his  employer. 
There  is  no  man  about  a  foundry  for  whom  we  have  more  pity 
than  a  poor  melter,  for  he  seldom  melts  two  heats  alike,  and  is 
cursed  by  the  piece  moulders  who  have  lost  their  work  through 
bad  iron.  Gibed  by  the  day  moulders,  lectured  by  the  fore- 
man, looked  black  at  by  his  emploper,  poorly  paid,  and  re- 
spected by  no  one  about  the  foundry,  his  lot  is  a  hard  one. 

A  poor  melter  is  not  always  to  blame  for  doing  poor  work, 
for  he  may  have  been  a  foundry  laborer  who  was  put  to  work 
as  a  melter,  and  never  given  proper  instruction  in  the  manage- 
ment of  a  cupola.  Again,  a  good  melter  may  be  made  a  poor 
one  from  being  interfered  with  by  others  who  do  not  under- 
stand melting.  Foundrymen  in  conversing  with  each  other 
learn  that  they  are  melting  ten  pounds  of  iron  to  the  pound  of 
fuel.  The  foundryman  not  being  a  practical  man,  does  not 
inquire  the  size  of  the  heat  or  cupola  in  which  it  is  melted,  the 
conditions  under  which  it  is  melted,  or  the  kind  of  work  the 
iron  is  for.  He  does  not  stop  to  think  that  the  other  foundry- 
man may  be  lying  to  him,  or  is  deceived  by  his  melter  and 

(254) 


MELTERS.  255 

does  not  know  how  many  pounds  of  iron  he  is  melting  to  the 
pound  of  fuel.  But  he  goes  to  his  foundry  and  insists  that  iron 
must  be  melted* at  a  ratio  of  10  to  I.  The  conditions  in  his 
foundry  may  be  totally  different  from  those  of  the  other  one, 
and  iron  may  not  be  melted  at  a  ratio  of  10  to  I  in  the  other 
foundry.  The  melter,  if  he  is  a  practical  man,  knows  this,  or 
finds  it  out  the  first  heat,  and  to  hold  his  job  shovels  in  extra 
fuel,  unbeknown  to  any  one,  and  if  he  is  watched,  does  not  get 
it  in  evenly  or  at  the  proper  time,  and  the  result  is  uneven  melt- 
ing and  dull  iron.  Foundrymen  do  not  always  furnish  their 
melters  with  proper  tools  for  chipping  out  and  making  up  the 
cupola,  a  suitable  material  for  repairing  and  keeping  up  the 
lining,  a  proper  flux  for  glazing  the  lining  and  making  the  cu- 
pola melt  and  chip  out  free,  and  a  man  who  would  be  a  good 
melter  if  given  a  chance,  is  frequently  made  a  poor  one  by 
being  hampered  in  his  work  for  want  of  tools  and  material  to 
work  with.  He  is  blamed  for  poor  melting  when  it  is  really  not 
his  fault.  Good  melters  frequently  get  into  a  rut  or  certain 
way  of  doing  their  work,  for  want  of  text-books  and  other  liter- 
ature on  melting  to  read  and  study,  or  association  with  men  of 
their  calling,  and  become  very  poor  melters.  As  a  lawyer  who 
does  not  read  law-books  that  are  up  to  the  times  and  associate 
with  his  colleagues,  becomes  a  pettifogger,  so  does  a  doctor 
who  does  not  study  his  text- books  and  medical  literature,  diag- 
noses all  cases  as  one  of  two  or  three  diseases,  has  one  or  two 
prescriptions  which  he  prescribes  for  all  cases.  The  man  of 
learning,  or  a  man  who  knows  it  all,  when  left  to  himself  for 
years  gets  to  know  nothing ;  and  so  it  is  with  melters  when  left 
to  themselves.  They  forget  many  things  they  are  not  called 
upon  to  practice  every  day,  and  in  time  get  into  a  rut  or  routine 
from  which  they  unconsciously  gradually  degenerate  if  the  mind 
is  not  refreshed  by  reading  or  contact  with  other  melters.  It 
should  be  the  aim  of  every  melter  to  converse  with  other 
melters  upon  cupola  matters  at  every  opportunity,  and  to  read 
and  study  all  literature  upon  the  subject,  whether  good  or  bad ; 
for,  if  good,  he  may  learn  something  new,  and,  if  bad,  it  stimu- 


256  THE    CUPOLA    FURNACE. 

lates  the  mind  to  reason  why  it  is  not  good,  and  how  it  can  be 
improved  upon.  It  recalls  to  mind  facts  in  his  own  experience 
which  have  long  been  forgotten,  and  he  learns  something,  at  all 
,  events.  It  is  to  the  interest  of  every  foundryman  who  depends 
upon  his  melter  for  results  to  keep  him  posted  upon  all  that  is 
new  in  the  business,  and  he  should  furnish  him  all  the  new  lit- 
erature on  the  subject  that  comes  into  his  office  or  is  published. 


CHAPTER  XVII. 

EXPLOSION    OF    MOLTEN    IRON. 

MOLTEN  iron  is  a  very  explosive  body,  and  under  certain 
conditions  explodes  with  as  loud  a  report  and  as  much  vio- 
lence as  gunpowder.  Under  other  conditions  it  is  not  at  all 
explosive,  but  the  conditions  under  which  it  explodes  must  be 
fully  understood  and  avoided  by  melters  and  moulders  to  pre- 
vent dangerous  accidents. 

A  stream  of  iron  flows  from  a  tap-hole  and  spout  smoothly 
if  the  front  and  spout  lining  have  been  properly  dried.  When 
wet  the  iron  explodes  as  it  emerges  from  the  tap  hole  and  is 
thrown  in  small  particles  some  distance  from  the  cupola.  The 
instant  a  stream  of  iron  strikes  a  wet  spout  it  explodes  and  the 
entire  stream  is  thrown  from  the  spout  in  all  directions  with 
great  force.  In  a  damp  spout  the  iron  boils  and  small  particles 
may  be  thrown  off,  but  the  explosion  is  not  so  violent  as  from 
a  wet  spout. 

A  wet  bod  causes  molten  iron  to  explode  the  instant  it 
comes  in  contact  with  the  stream,  and  it  is  impossible  to  close 
a  tap  hole  with  it.  A  bod  containing  a  little  too  much  mois- 
ture causes  a  less  violent  explosion  and  a  tap  hole  may  be 
closed  with  it,  but  in  closing  it,  the  iron  explodes  and  is  fre- 
quently thrown  from  the  tap  hole  with  great  force  past  the 
sides  of  the  bod  before  it  is  pressed  into  the  hole.  When  the 
bod  is  in  place  in  the  hole  one  or  more  small  explosions  fre- 
quently take  place,  and  the  bod-stick  must  be  firmly  held 
against  the  bod  to  prevent  it  being  blown  out.  The  kick  or 
thump  felt  against  the  end  of  a  bod-stick  when  pressing  a  bod 
into  place  is  due  to  these  explosions,  and  not  to  the  pressure 
of  molten  iron  in  the  cupola,  as  is  generally  supposed.  Bod 
17  (257) 


258  THE   CUPOLA   FURNACE. 

material  should  be  no  wetter  than  moulding  sand  properly  tem- 
pered for  moulding. 

When  the  iron  is  very  hard,  a  stream  of  very  hot  iron  throws 
off  a  great  many  sparks  from  a  dry  spout.  These  sparks  are 
caused  by  an  explosion  of  the  iron  due  to  the  combination  of 
oxygen  with  the  combined  carbon  of  the  iron,  and  the  sparks 
are  the  oxide  of  iron.  They  contain  very  little  heat,  and  melters 
or  moulders  do  not  hesitate  to  enter  showers  of  these  sparks  to 
stop  in  or  catch  the  stream  of  iron.  The  sparks  from  explo- 
sions caused  by  dampness  are  of  an  entirely  different  character, 
and  burn  the  flesh  or  clothing  wherever  they  strike. 

A  wet,  cold  or  rusted  tapping  bar  thrust  into  a  stream  of  iron 
in  the  tap  hole  or  spout,  causes  the  iron  to  explode.  Tap  bars 
should,  therefore,  always  be  heated  before  they  are  put  into  the 
stream  of  iron. 

When  iron  falls  from  a  spout  upon  a  hard  floor,  it  spatters 
and  flies  in  small  particles  to  a  considerable  distance  from  the 
place  it  first  strikes,  and  it  is  dangerous  to  go  near  the  spout  as 
long  as  the  stream  is  falling  upon  the  floor. 

When  iron  falls  from  a  spout  upon  a  wet,  muddy  floor,  it  ex- 
plodes instantly,  and  small  particles  of  molten  iron  may  thus  be 
thrown  a  hundred  feet  from  the  cupola.  If  the  stream  continues 
to  run  upon  the  floor,  one  explosion  follows  another  in  rapid 
succession,  or  a  pool  of  molten  iron  is  formed,  which  boils  and 
explodes  every  few  minutes,  as  long  as  there  is  any  moisture  in 
the  floor  and  the  iron  remains  liquid.  The  floor  under  a  spout 
should  always  be  made  of  loose  dry  sand,  with  a  hole  in  it  to 
catch  any  iron  that  falls  from  the  spout. 

The  floor  under  a  cupola  should  always  be  dry,  and  when 
paved  with  brick  or  stone,  should  be  covered  with  an  inch  or 
two  of  dry  sand  before  dumping,  to  prevent  fluid  iron  or  slag 
in  the  bottom  of  the  cupola  spattering  or  exploding  when 
dumped. 

Molten  iron  explodes  violently  when  a  piece  of  cold,  wet  or 
rusted  iron  is  thrust  suddenly  into  it,  as  the  writer  has  reason 
to  know  from  practical  experience,  when  working  at  stove 


EXPLOSION    OF    MOLTEN    IRON.  259 

moulding  in  the  winter  of  1866  and  1867.  Knowing  that  a  rusty 
or  wet  skimmer  made  iron  explode,  we  always  took  the  pre- 
caution of  putting  our  skimmers  into  the  foundry  heating  stove 
and  heating  them  to  a  red  heat  before  catching  iron.  One  day 
we  had  taken  the  precaution,  heating  a  skimmer  to  a  red  heat 
and  putting  it  in  a  convenient  place  for  use.  A  small  boy  who 
was  around  the  foundry  and  sometimes  skimmed  our  iron  before 
pouring,  saw  the  red-hot  skimmer,  and  took  it  out  and  put  it  in 
the  snow,  while  we  were  catching  a  ladle  of  iron,  As  soon  as 
we  set  the  ladle  on  the  floor  he  ran  in  with  the  skimmer  dripping 
wet,  and  before  we  could  prevent  him,  thrust  it  into  the  molten 
iron.  The  iron  exploded  instantly  and  was  thrown  all  over  us 
as  we  leaned  over  the  ladle,  burning  us  so  severely  that  we  were 
not  able  to  be  out  of  the  house  for  several  weeks,  and  we  still 
carry  many  scars  from  those  burns.  The  iron  was  thrown  with 
great  violence,  and  passed  through  our  clothing  and  a  thick  felt 
hat,  like  shot  from  a  gun.  The  exploded  iron  passed  over  the 
boy's  head  and  he  was  burned  slightly,  but  never  was  seen 
about  the  foundry  again,  and  probably  never  became  an  iron 
moulder. 

Molten  iron  when  poured  into  a  damp  or  rusted  chill-mould 
or  a  wet  sand-mould,  explodes  and  is  thrown  from  the  mould, 
and  escaping  from  a  mould  upon  a  wet  floor  or  into  the  bot- 
tom of  a  wet  pit,  explodes.  In  the  foundry  of  Wm.  McGilvery 
&  Company,  Sharon,  Pa.,  a  deep  pit  for  casting  rolls  on  end 
was  put  in  the  foundry  floor  and  lined  with  boiler  plate.  The 
first  roll  cast  in  this  pit  was  one  eleven  feet  long,  weighing 
about  five  tons,  moulded  in  a  flask  constructed  in  ring  sections 
and  clamped  together.  The  mould  was  not  properly  made  and 
clamped,  and  when  almost  filled  with  molten  iron  gave  way 
near  the  bottom  and  permitted  the  iron  to  escape  into  the  pit, 
the  bottom  of  which  was  covered  with  wet  sand  or  mud.  The 
iron  at  once  exploded  and  forced  its  way  up  through  ten  feet 
of  sand  that  had  been  rammed  about  the  mould  in  the  pit,  and 
was  thrown  up  to  the  foundry  roof  at  a  height  of  forty  feet.  The 
molten  iron  continued  to  explode  until  fully  four  tons  were 


260  THE   CUPOLA    FURNACE. 

thrown  from  the  pit  in  small  particles,  and  the  foundry  burned 
to  the  ground. 

Molten  iron  explodes  when  poured  into  mud  or  brought  in 
contact  with  wet  rusted  scrap,  but  does  not  explode  when 
poured  into  deep  or  clean  water.  At  a  small  foundry  that 
stood  near  the  Pittsburg  &  Erie  canal,  in  Sharon,  Pa.,  many 
years  ago  a  wager  was  made  by  two  moulders  that  molten 
iron  could  not  be  poured  into  the  water  of  the  canal  without 
exploding.  A  ladle  of  iron  was  accordingly  taken  to  the 
canal  and  poured  into  the  water  without  any  explosion  taking 
place.  A  few  days  later  an  apprentice  boy  who  had  witnessed 
this  experiment  undertook  to  pour  some  into  water  in  an  old 
salt  kettle  that  sat  in  the  yard  near  the  foundry  and  contained 
rusted  scrap  and  mud  under  the  water.  An  explosion  at  once 
took  place  that  almost  wrecked  the  foundry.  The  water  in  this 
case  was  not  of  sufficient  depth  to  destroy  the  explosive  pro- 
perty of  the  molten  metal  before  it  came  in  contact  with  the 
rusted  scrap  and  mud  at  the  bottom  of  the  kettle. 

Moulders  frequently  pour  the  little  iron  they  have  left  over, 
after  pouring  off  their  day's  work,  into  a  bucket  of  water  to 
heat  the  water  for  washing  in  cold  weather.  This  was  a  com- 
mon practice  of  the  moulders  in  the  foundry  of  James  Marsh, 
Lewisburg,  Pa.,  until  one  day  iron  was  poured  into  a  bucket  of 
water  in  which  clay  wash  had  been  mixed  and  contained  mud 
at  the  bottom.  It  exploded  instantly  with  so  great  a  violence 
that  all  the  windows  were  blown  out  of  the  foundry,  and  this 
stopped  the  heating  of  water  for  washing,  in  that  way,  at  that 
foundry. 

At  another  foundry,  iron  poured  into  clear  water  in  a  rusted 
cast-iron  pot  exploded,  doing  great  damage. 

At  the  foundry  of  North  Bros.,  Philadelphia,  Pa.,  during  the 
flood  in  the  Schuylkill  river  June,  1895,  the  cupola  was  pre- 
pared for  a  heat  and  the  blast  put  on  ;  but  before  the  heat  could 
be  poured  off  water  soaked  into  the  cupola  pit  and  had  to  be 
bailed  out  to  prevent  the  pit  being  filled.  The  heat  was  all 
poured  before  water  came  upon  the  moulding  floors,  but  the 


EXPLOSION   OF    MOLTEN    IRON.  261 

bottom  of  the  cupola  pit  was  soaking  wet,  and  the  melter,  in  his 
eagerness  to  leave  the  foundry  before  it  was  flooded,  dropped 
the  bottom  without  drawing  off  the  molten  iron  remaining  in 
the  cupola.  The  instant  the  molten  iron  and  slag  dumped  from 
the  cupola  came  in  contact  with  the  wet  floor  of  the  pit,  a  vio- 
lent explosion  took  place,  scattering  molten  iron,  slag  and  fuel 
in  all  directions  and  blowing  all  the  windows  out  of  the  foundry. 
Had  the  melter  taken  the  precaution  to  have  drawn  off  all  the 
molten  iron  before  dumping,  and  thrown  a  few  shovelfuls  of  dry 
sand  under  the  cupola  to  receive  the  first  slag  to  fall  upon  the 
bottom,  this  explosion  would  not  have  taken  place. 

At  the  foundry  of  The  Skinner  Engine  Co.,  Erie,  Pa.,  a  vio- 
lent explosion  took  place  in  their  cupola  which  almost  entirely 
wrecked  it.  At  the  time  of  this  explosion,  a  lot  of  small 
steam  cylinders  were  being  melted  in  the  cupola,  and  in  some 
of  these  cylinders  the  ports  of  the  steam-chest  had  been  closed 
by  rust,  leaving  the  steam-chest  filled  with  water,  from  which 
it  could  not  escape.  The  foreman,  David  Smith,  had  given 
the  melter  orders  to  see  that  each  of  these  cylinders  was 
broken  before  being  put  into  the  cupola,  but  this  order  had  by 
the  melter  been  disregarded,  and  the  explosion  was  attributed 
to  the  water  confined  in  one  of  the  cylinders  being  converted 
into  steam  and  exploding  with  such  violence  as  to  wreck  the 
cupola. 

At  the  foundry  of  The  Buffalo  School  Furniture  Co.,  Buffalo, 
N.  Y.,  an  explosion  took  place  in  1895  in  their  sixty-inch  cupola, 
about  seven  minutes  after  the  blast  was  put  on  for  a  heat,  which 
blew  the  heavy  cast  iron  door  from  the  tuyere  box,  on  each 
side  of  the  cupola ;  and  also  blew  out  the  front  and  broke  the 
heavy  cast-iron  bottom  doors.  A  number  of  men  who  chanced 
to  be  near  the  cupola  were  severely  burned,  but  fortunately 
none  were  killed.  This  explosion  was  attributed  to  a  number 
of  causes,  one  which  was  the  formation  of  gas  in  the  cupola  be- 
fore the  blast  was  put  on,  which  was  exploded  by  the  addition 
of  oxygen  from  the  blast.  But  this  could  hardly  have  been  the 
cause,  for  the  blast  had  been  on  fully  seven  minutes  before  the 


262  THE   CUPOLA   FURNACE. 

explosion  occurred,  and  had  this  been  the  cause  the  explosion 
would  have  taken  place  almost  as  soon  as  the  blast  was  put  on. 
Another  cause  given  for  the  explosion  was  that  dynamite  had 
been  placed  in  the  cupola  concealed  in  some  pieces  of  scrap- 
iron.  This  may  have  been  the  case,  or  some  other  explosive 
body  may  have  been  concealed  in  the  scrap;  but  it  is  just  as 
probable  that  it  was  due  to  steam  generated  from  water  con- 
fined in  some  piece  of  the  scrap,  by  rusting  of  the  opening 
through  which  it  was  admitted  to  the  casting;  as  in  the  case  at 
the  foundry  of  The  Skinner  Engine  Co. 

A  damp  ladle  causes  iron  to  boil,  and  if  the  daubing  is  very 
thick  may  cause  it  to  explode.  A  wet  daubing  or  water  in  a 
ladle  explodes  the  iron  the  instant  it  touches  it.  Wet  or  rusted 
scrap  iron  placed  in  a  ladle  to  chill  the  molten  iron,  causes  the 
iron  if  tapped  upon  it,  or  if  thrown  into  a  ladle  of  iron,  to  ex- 
plode. Such  an  explosion  may  be  prevented  by  heating  the 
scrap  to  a  red  heat  just  before  using  it  to  chill  the  iron. 


CHAPTER  XVIII. 

SPARK  CATCHING  DEVICES  FOR  CUPOLAS. 

FOUNDRYMEN,  whose  plants  are  located  in  closely  built  up 
neighborhoods,  are  very  much  annoyed  by  sparks  thrown  out 
of  their  cupolas  lighting  upon  the  roofs  of  adjoining  buildings 
and  setting  them  on  fire.  In  some  cases  they  have  on  this 
account  been  compelled  to  move  their  plants  from  towns  and 
cities  to  the  suburbs.  Many  plans  have  been  devised  and  tried 
for  arresting  these  sparks ;  one  of  the  oldest  and  most  efficient 
of  which  is  the  design  shown  in  Fig.  55.  This  arrangement  was 
devised  when  the  old-fashioned  cupolas  with  brick  stack  were 
in  vogue,  and  was  generally  put  up  in  such  cases  where  cupola 
sparks  were  very  objectionable.  It  consisted  in  constructing  the 
stack  upon  an  iron  plate  supported  by  iron  columns,  on  a  level 
with  the  top  of  the  cupola.  The  end  of  this  plate  extended  over 
the  top  of  the  cupola,  with  an  opening  in  the  plate  equal  to  the 
inside  diameter  of  the  cupola,  and  on  the  plate  was  put  a  short 
stack,  in  which  was  placed  the  charging  door,  the  top  of  which 
was  arched  over  toward  the  main  stack,  with  which  it  connected 
on  the  side. 

Any  sparks  that  arose  from  the  cupola  were  thrown  into  the 
bottom  of  the  main  stack  by  the  arch  in  the  direction  indicated 
by  the  arrows  and  were  removed  when  cold,  as  often  as  the 
bottom  of  the  stack  filled  up  to  such  an  extent  as  to  interfere 
with  the  arrest  of  the  sparks. 

This  arrangement  was  very  effective  in  arresting  sparks,  but 
was  not  found  to  be  a  very  convenient  one  for  attaching  to  our 
modern  cupolas,  and  numerous  other  plans  have  since  been 
devised  and  used. 

c  263  > 


264 


THE   CUPOLA    FURNACE. 
Fin.  55. 


SPARK   CATCHER    IN    OLD    STYLE   CUPOLA. 


SPARK  CATCHING  DEVICE  FOR  MODERN  CUPOLAS. 

In  Fig  56  is  seen  a  more  modern  spark-arrester  than  the  one 
just  described.     In  this  device,  the  casing  is  cut  in  two  at  the 


SPARK   CATCHING   DEVICES    FOR    CUPOLAS.  265 

FIG.  56. 


SPARK    CATCHING    DEVICE   IN    MODERN    CUPOLA. 


266  THE    CUPOLA    FURNACE. 

bottom  of  the  charging  door  and  an  iron  plate  or  ring  placed 
upon  the  top  of  the  cupola  casing,  where  it  is  supported  by 
the  casing  and  cast-iron  brackets  riveted  or  bolted  to  it  on  the 
outside.  The  inside  of  the  plate  or  ring  generally  covers  the 
top  of  the  cupola  lining  to  protect  it  when  charging  the  stock, 
and  the  outside  extends  over  the  cupola  casing  from  six  to 
twelve  inches.  On  this  plate  the  stack  casing,  which  is  of 
larger  diameter  than  the  cupola  casing,  is  placed  and  lined 
with  a  thin  lining.  The  spark-arresting  device  consists  in 
making  the  stack  larger  than  the  cupola  so  that  the  blast  loses 
its  force  when  it  emerges  from  the  cupola,  and  enters  the  stack, 
and  the  sparks  carried  out  of  the  cupola  fall  back  into  it  before 
reaching  the  top  of  the  stack.  The  extent  to  which  the  stack 
should  be  enlarged  to  be  effective  in  arresting  sparks  depends 
upon  the  height  of  it;  low  stacks  requiring  to  be  of  a  larger 
diameter  than  high  ones. 

In  this  illustration  is  shown  a  very  neat  arrangement  for  sup- 
plying blast  to  a  cupola  when  a  belt  air  chamber  riveted  to  the 
cupola  shell  is  not  used.  The  main  blast  pipe  AA  which 
encircles  the  cupola  is  placed  up  out  of  the  way,  in  catching 
iron  or  removing  large  ladles.  The  branch  pipes  are  cast  in 
one  piece  and  tightly  bolted  or  riveted  to  the  main  pipe  and 
cupola  casing,  to  prevent  the  escape  of  blast.  The  peep  holes 
BB  are  cast  in  the  pipe,  and  close  with  a  tight- fitting  swing  cap 
and  latch. 

RETURN    FLUE    CAPULA    SPARK  CATCHER. 

'  In  Fig.  57  is  shown  a  device  designed  by  John  O'Keefe, 
Superintendent  of  Perry  &  Go's  Stove  Works,  Albany,  N.  Y., 
for  catching  sparks  and  saving  fuel.  The  foundry  of  the  firm 
in  which  this  device  was  constructed,  was  located  on  Hudson 
St.,  in  a  closely  built  up  part  of  the  city,  and  they  were  very 
much  annoyed  by  sparks  from  their  cupola  setting  fire  to  roofs 
of  buildings  in  the  vicinity,  and  it  became  necessary  to  prevent 
sparks  escaping  or  move  their  foundry.  A  number  of  devices, 
such  as  hoods,  etc.,  were  tried,  but  none  of  these  proved  effect- 
ive, and  a  return  flue  was  constructed.  The  arch  or  dome  A  was 


SPARK   CATCHING   DEVICES    FOR   CUPOLAS.  267 

Fig-  57- 


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RETURN  FLUE  CAPULA  SPARK  CATCHER. 


268  THE   CUPOLA    FURNACE. 

thrown  across  the  cupola  stack  above  the  door,  and  the  flue  B  led 
out  of  the  cupola  just  below  the  dome  and  down  to  the  foundry 
floor,  from  which  point  it  returned  to  the  stack  above  the  dome. 
When  the  cupola  was  in  blast,  waste  heat  from  the  cupola 
struck  the  dome  and  was  thrown  back  upon  the  stock  in  the 
cupola,  or  was  forced  down  through  the  flue  B  and  returned  to 
the  cupola  stack  through  the  flue  C  above  the  dome.  When 
the  cupola  was  put  in  blast  it  was  found  that  so  large  an  amount 
of  heat  and  gas  escaped  from  the  door  that  the  cupola  could 
not  be  charged  when  in  blast,  and  it  became  necessary  to  make 
a  small  opening  through  the  dome  to  permit  part  of  it  to  es- 
cape. Had  the  cupola  been  of  a  size  to  admit  of  all  the  stock 
being  charged  before  the  blast  was  put  on  and  the  door  closed, 
during  the  heat,  there  is  no  doubt  considerable  fuel  might  have 
been  saved,  and  faster  melting  done.  But  as  it  was,  no  fuel 
was  saved,  and  there  was  no  perceptible  change  in  the  time  re- 
quired to  melt  a  heat.  The  device  was  effective  in  preventing 
the  escape  of  sparks  and  small  pieces  of  fuel  from  the  stack,  for 
they  were  all  thrown  back  into  the  cupola  or  deposited  in  the 
bottom  of  the  flue,  from  which  they  were  removed  through  the 
opening  D  at  the  bottom  of  the  flue,  as  frequently  as  found 
necessary. 

OTHER  SPARK  CATCHING  DEVICES. 

Another  device  for  arresting  sparks  is  to  place  a  half  circle 
fire-brick  arch  opened  at  both  ends  on  the  top  of  the  stack, 
making  its  total  length  and  breadth  equal  to  the  outside 
diameter  of  the  stack.  This  plan  arrests  the  sparks  in  their 
upward  course  and  some  of  them  fall  back  into  the  cupola, 
but  many  are  carried  out  at  the  ends  of  the  arch  by  the  blast 
and  fall  upon  the  foundry  roof,  and  on  windy  days  may  be 
carried  to  adjoining  roofs. 

Iron  caps  or  hoods  are  also  placed  one  or  more  feet  above 
the  top  of  cupola  stacks  to  arrest  sparks ;  but  they,  like  the 
arch,  only  arrest  the  sparks  in  their  upward  flight  and  throw 
many  of  them  down  upon  the  foundry  or  scaffold  roof. 

Another  plan  for  preventing  the  escape  of  sparks  is  to  sus- 


SPARK   CATCHING   DEVICES    FOR   CUPOLAS.  269 

pend  an  iron  disk  of  a  few  inches  smaller  diameter  than  the 
stack  in  the  stack  near  the  top.  The  sparks  strike  this  disk 
and  are  thrown  back  into  the  cupola.  But  this  device  cannot 
be  used  in  contracted  stacks  with  a  strong  blast,  and  in  large 
ones  the  cohesive  properties  of  the  iron  are  soon  destroyed  by 
the  heat  and  gases  of  the  cupola,  and  if  not  frequently  replaced 
there  is  danger  of  it  breaking  from  the  jar  in  chipping  out  the 
cupola,  and  falling  upon  the  melter. 

THE  BEST  SPARK  CATCHING  DEVICE. 

The  cause  of  sparks  being  thrown  from  a  cupola  is  the 
strong  blast  forced  into  the  cupola  at  the  tuyeres,  which 
carries  small  pieces  of  fuel  out  at  the  top  of  the  stack  during 
the  heat,  and  large  pieces  near  the  end  of  a  heat,  when  the 
stock  is  low  in  the  cupola  and  the  blast  passes  through  it  more 
freely.  The  lifting  power  of  the  blast  is  increased  by  confining 
it  in  a  contracted  stack,  and  good-sized  pieces  of  fuel  may  be 
thrown  several  feet  above  the  top  of  a  small  stack ;  but  the  in- 
stant the  blast  escapes  from  the  top  of  the  stack  it  expands 
and  its  lifting  power  is  lost,  and  sparks  or  pieces  of  fuel  fall  by 
their  own  weight  and  may  in  their  descent  be  carried  to  some 
distance  by  a  strong  wind. 

To  prevent  them  being  carried  out  of  the  stack,  it  is  only 
necessary  to  provide  sufficient  room  in  the  stack  for  the  blast 
to  expand,  after  escaping  from  the  cupola,  and  lose  its  lifting 
force,  when  the  sparks  will  fall  back  in  the  cupola  and  be  con- 
sumed. This  may  be  done  by  constructing  the  stack  casing  of 
the  same  diameter  as  the  cupola  casing,  and  lining  it  with  a 
thin  lining  of  four-inch  fire-brick  supported  by  angle  iron,  so 
that  the  cupola  lining  may  be  removed  or  repaired  without  dis- 
turbing the  stack  lining.  Cupolas  constructed  in  this  way, 
when  the  stack  is  of  proper  height,  do  not  throw  out  sparks. 
When  it  is  not  desirable  to  have  a  very  high  stack,  the  enlarged 
stack  shown  in  Fig.  56  may  be  used.  The  first  cost  of  a  stack 
of  this  kind  is  a  little  greater  than  that  of  a  contracted  one, 
but  when  properly  constructed  and  lined,  will  last  the  life  of  a 


2/0  THE   CUPOLA    FURNACE. 

cupola.  In  fact  we  never  knew  one,  if  properly  lined  when 
constructed,  requiring  to  be  relined  or  repaired,  and  the  saving 
effect  by  preventing  damage  to  roofs,  lumber,  flasks,  etc., 
from  sparks  will  soon  pay  for  the  extra  cost  of  construction. 
The  objection  usually  made  by  foundrymen  to  large  stacks  is 
that  they  do  not  give  sufficient  draught  for  lighting  up.  This 
may  be  the  case  when  the  top  of  the  stack  is  only  a  few  feet 
above  the  charging  door,  but  when  given  a  proper  height  for 
arresting  sparks  there  is  always  sufficient  draught  for  lighting 
up.  There  are  many  cupolas  constructed  upon  this  plan  in 
use  at  the  present  time,  and  they  give  better  satisfaction  than 
those  with  contracted  stack. 


CHAPTER  XIX. 

HOT    BLAST   CUPOLAS. 

A  NUMBER  of  plans  have  in  this  country  been  at  different 
periods  devised  for  utilizing  the  heat  escaping  from  the  top  of  a 
cupola  when  in  blast,  for  heating  the  blast  before  entering  the 
cupola  at  the  tuyeres.  The  best  arranged  cupolas  of  this  kind 
that  we  have  seen  are  those  shown  in  Fig.  58.  This  pair  of 
cupolas  was  made  at  Albany,  N.  Y.,  by  the  firm  of  Jagger, 
Treadwell  &  Perry.  With  a  view  of  saving  fuel  and  improving 
the  quality  of  iron  for  light  work,  the  two  cupolas  DD  of  thirty 
and  forty- five  inches  diameter,  respectively,  inside  the  lining, 
and  eight  feet  high  were  constructed,  and  were  made  of  boiler 
plate ;  the  bottom  and  top  plates  between  which  the  cupolas 
were  placed  were  supported  by  four  iron  columns,  and  on  the 
top  plate  were  fitted  the  brick  arches  BB,  which  connected  the 
cupolas  with  the  brick  ovens  EE.  In  the  rear  of  each  cupola, 
between  the  ovens,  was  placed  the  high  stack  A.  Each  oven 
was  filled  with  cast-iron  pipe  CC,  through  which  the  blast 
passed  before  entering  the  cupolas.  When  in  blast,  the  escaping 
heat  from  the  cupolas  passed  downward  through  the  ovens  as 
indicated  by  the  arrows,  and  entered  the  stack  A  from  the 
bottom  of  the  ovens.  The  pipes  were  by  the  escaping  heat 
carried  up  to  a  red  heat,  and  the  blast  in  passing  through  these 
coils  of  pipe  was  heated  to  a  sufficient  degree  before  entering 
the  cupolas  to  melt  lead.  This  plan  was  a  success  so  far  as 
heating  the  blast  was  concerned,  but  the  blast  could  not  be 
carried  up  to  the  above  degree  until  the  cupolas  had  been  in 
blast  for  some  time.  Hence  very  little  fuel  was  saved,  for  no 
economy  in  fuel  could  be  effected  until  the  blast  was  heated, 
and  the  cupolas  had  to  be  fully  charged  with  fuel  for  the  first 

(271) 


2/2 


THE   CUPOLA    FURNACE. 
FIG.  58. 


HOT  BLAST  CUPOLAS. 


HOT   BLAST   CUPOLAS,  273 

half  of  the  heat.  No  perceptible  improvement  was  made  in  the 
quality  of  the  iron  by  the  heating  of  the  blast,  and  the  greatest 
objection  to  these  cupolas  was  the  difficulty  of  keeping  the  coils 
of  pipe  intact.  The  heating  of  the  pipe  to  a  red  heat  every 
time  the  cupolas  were  put  in  blast  and  permitting  them  to  cool 
before  the  next  heat,  in  a  short  time  destroyed  the  cohesive 
properties  of  the  iron,  and  the  pipe  frequently  broke  after  or 
during  a  heat  and  permitted  the  blast  to  escape  into  the  oven. 
These  breaks  became  so  frequent  and  annoying  after  the  pipe 
had  been  in  use  for  a  short  time,  and  were  so  expensive  to  re- 
pair, that  the  slight  saving  effected  in  fuel  did  not  justify  a  con- 
tinued use  of  the  hot  blast,  and  it  was  abandoned.  The  cupolas 
were  for  a  long  time  used  without  the  hot  blast,  and  the  ovens 
proved  excellent  spark  catchers.  No  sparks  were  ever  thrown 
from  the  top  of  the  high  stack,  and  the  ovens  had  frequently  to 
be  cleaned  to  remove  them. 

At  the  stove  foundry  of  Ransom  &  Co.,  Albany,  N.  Y.,  a 
cupola  was  constructed  with  a  large  stack,  and  coils  of  pipe  for 
heating  the  blast  were  placed  in  the  stack  directly  over  the 
cupola.  The  blast  when  passed  through  these  pipes  was  heated 
to  a  high  degree  after  the  cupola  had  been  in  blast  for  a  short 
time,  but  the  pipes  in  this  case  broke  after  repeated  heating  and 
cooling,  as  in  the  ovens  of  the  Jagger,  Treadvvell  and  Perry 
cupolas,  and  after  the  killing  of  a  melter,  by  a  piece  of  pipe 
falling  upon  him  from  the  stack  while  picking  out  the  cupola, 
the  pipes  were  all  removed  from  the  stack  and  heating  of  the 
blast  was  discontinued.  Several  attempts  have  been  made  to 
take  the  escaping  heat  direct  from  the  top  of  a  cupola  and  re- 
turn it  into  the  cupola  through  the  tuyeres;  but  in  all  cases 
this  plan  has,  for  lack  of  means  to  force  the  hot  air  into  the 
cupola,  proven  a  failure. 

Exhaust  pipes  have  been  connected  with  the  stack  of  a  cupola 
and  the  inlets  of  the  blower  placed  near  the  cupola,  and  hot  air 
drawn  from  the  stack  by  the  blower  and  returned  to  the  cupola 
through  the  tuyeres.  This  arrangement  supplied  a  hot  blast  to 
the  cupola  with  no  expense  for  heating  the  blast,  and  was  in  the 
18 


274  THE   CUPOLA   FURNACE. 

early  part  of  a  heat  in  which  it  was  tried,  a  success,  when  only 
a  small  amount  of  heat  escaped  from  the  cupola  and  the  air 
drawn  from  the  stack  was  heated  only  to  a  limited  extent. 
But,  as  the  melting  progressed  and  the  stock  settled  low  in  the 
cupola,  the  air  drawn  from  the  stack  was  heaten  to  so  high  a 
a  degree  as  to  heat  and  destroy  a  blower  through  which  it  was 
passed  in  being  returned  to  the  cupola.  Could  hot  air  have 
been  taken  from  a  cupola  stack  and  returned  to  the  cupola 
through  the  tuyeres  without  passing  it  through  a  blower,  it 
would,  no  doubt,  have  effected  a  great  saving  in  fuel  in  the  days 
of  low  cupolas,  when  a  large  amount  of  the  heat  from  fuel  direct 
was  not  utilized  in  melting.  But  this  could  not  be  done,  and 
after  a  number  of  experiments  to  secure  a  hot  blast  in  this  way. 
the  plan  was  given  up  as  a  failure. 

The  blast  for  a  cupola  can  be  heated  in  a  hot-blast  oven  simi- 
lar to  those  some  years  ago  used  in  heating  the  blast  for  fur- 
naces, and  which  was  done  by  furnaces  specially  constructed 
for  the  purpose,  and  not  with  gas  taken  from  the  furnaces  as  at 
the  present  time.  But  these  ovens  would  be  required  to  be 
kept  continually  hot  to  prevent  breakage  of  the  pipes  by  re- 
peated heating  and  cooling.  The  saving  of  fuel  effected  in 
melting  with  a  hot  blast  obtained  in  this  manner,  would  not  be 
sufficient  to  pay  for  the  expense  of  heating  the  blast  for  a  cupola 
that  is  only  in  blast  for  a  few  hours  each  day;  and  it  is  doubtful 
if  the  saving  effected  would  justify  the  heating  of  the  blast,  if  a 
cupola  was  kept  constantly  in  blast,  or  the  hot  blast  changed 
from  one  cupola  to  another  as  soon  as  the  heat  was  melted. 

WASTE  HEAT  FROM  A  CUPOLA. 

A  number  of  plans  for  utilizing  the  heat  escaping  from  a 
cupola,  besides  using  it  for  heating  the  blast,  have  been  devised  ; 
such  as  utilizing  it  for  heating  the  iron  before  charging  it  into 
the  cupola,  drying  cores,  ladles,  etc.  All  these  experiments 
were  made  years  ago,  when  from  six  to  ten  feet  was  considered 
to  be  the  proper  height  for  a  cupola,  and  fully  one-half  of  the 
heat  escaped  from  the  top ;  but  it  was  not  until  the  height  of 


HOT   BLAST   CUPOLAS.  275 

cupolas  was  increased  that  a  practical  means  of  utilizing  all  the 
heat  of  the  fuel  in  melting  was  found.  In  a  high  cupola  all  the 
heat  escaping  from  the  melting  zone  is  utilized  to  heat  the  stock 
in  the  cupola  and  prepare  it  for  melting  before  the  stock  settles 
into  the  melting  zone.  The  height  that  a  cupola  should  be 
made  in  order  to  utilize  all  the  heat  depends  upon  its  diameter, 
volume  of  blast,  and  the  way  in  which  the  stock  is  charged. 
Cupolas  of  twelve  to  twenty  inches  in  diameter  must  be  made 
low,  so  that  the  stock  in  case  it  hangs  up  in  the  cupola  may  be 
dislodged  with  the  bar,  and  all  the  heat  cannot  be  utilized  in 
these  small  cupolas  except  when  a  very  small  volume  of  blast  is 
used.  In  this  latter  case  the  melting  is  slow,  and  it  is  more 
economical  to  permit  part  of  the  heat  to  escape,  and  do  fast 
melting  with  a  strong  blast.  Cupolas  of  large  diameter  may  be 
made  of  a  sufficient  height  to  utilize  all  the  heat,  no  matter  how 
great  the  volume  of  blast  or  how  openly  the  stock  is  charged. 
Cupolas  of  large  diameter  now  in  use  in  many  foundries  are 
from  fifteen  to  twenty  feet  high,  and  those  in  the  Carnegie  Steel 
Works,  Homestead,  Pa.,  are  thirty  feet  high.  In  these  cupolas 
whole  bars  of  pig  iron  are  charged,  and  all  the  stock  is  dumped 
into  the  cupola  from  barrows,  and  no  pains  taken  to  pack  it 
close  to  prevent  the  escape  of  heat.  Yet  no  heat  escapes  from 
the  top  of  the  cupola  when  filled  with  stock,  and  it  has  not 
been  found  necessary  to  line  the  iron  stacks  with  brick  to  pre- 
vent them  being  heated  by  heat  escaping  from  the  cupolas. 

In  low  cupolas  heat  may  to  a  large  extent  be  prevented  from 
escaping  by  breaking  the  pig  and  scrap  into  small  pieces,  and 
when  charging  packing  it  close.  More  time  is  then  required 
for  the  heat  to  work  its  way  through  the  stock  in  escaping 
from  the  melting  zone,  and  a  greater  amount  of  it  is  utilized  in 
heating  the  stock  and  preparing  it  for  melting  before  it  settles 
into  the  melting  zone. 


CHAPTER  XX. 

TAKING  OFF  THE  BLAST  DURING  A  HEAT — BANKING  A  CUPOLA — 
BLAST  PIPES,  BLAST  GATES. 

EXPLOSIONS  IN  BLAST  PIPES,  BLAST  GAUGES,  BLAST  IN  MELTING. 

THE  length  of  time  the  blast  can  be  taken  off  a  cupola  after 
it  has  been  in  blast  long  enough  to  melt  iron,  and  put  on  again 
and  good  melting  done,  depends  upon  the  condition  of  the 
stock  in  the  cupola  at  the  time  it  has  been  stopped. 

The  blast  may  be  taken  off  a  cupola  that  has  only  been  in 
blast  for  a  short  time,  is  in  good  melting  condition  and  filled 
with  stock,  for  many  hours  if  the  melted  iron  and  slag  are  all 
drawn  off  and  the  tuyeres  carefully  closed  to  exclude  the  air 
and  prevent  melting  and  chilling  after  the  blast  has  been 
stopped.  We  have  known  a  cupola  in  this  condition  in  case 
of  a  break-down  in  the  blowing  machinery  to  be  held  from  four 
o'clock  in  the  afternoon  until  eight  o'clock  the  following  morn- 
ing, and  good  melting  done  when  the  blast  was  again  put  on. 

In  this  case,  the  tuyeres  were  packed  with  new  molding  sand 
rammed  in  solid  to  completely  exclude  the  air,  and  the  molten 
iron  all  drawn  off,  after  the  tuyeres  had  been  closed  for  a  short 
time  and  the  tap  hole  closed  with  a  bod.  Before  putting  on 
the  blast  in  the  morning,  the  tuyeres  were  permitted  to  remain 
open  for  a  short  time,  to  allow  any  gas  that  may  have  collected 
in  the  cupola  during  the  stoppage  to  escape  and  avoid  an  ex- 
plosion, which  might  have  occurred  had  a  large  volume  of  blast 
been  forced  into  the  cupola  when  filled  with  gas. 

Cupolas  that  have  been  in  blast  for  some  time  and  from 
which  the  blast  is  removed  toward  the  end  of  the  heat  when 
the  cupola  is  comparatively  empty,  or  in  bad  shape  for  melt- 
ing, cannot  be  held  for  any  great  length  of  time,  even  if  the 

(276) 


TAKING   OFF  THE    BLAST    DURING   A    HEAT.  277 

tuyeres  are  at  once  closed  and  every  precaution  taken  to  pre- 
vent chilling  and  clogging.  This  is  due  to  the  gradual  settling 
of  a  semi-fluid  slag  and  cinder  above  the  tuyeres,  and  the  clos- 
ing up  of  small  openings  in  it  through  which  the  blast  was  dis- 
tributed to  the  stock  ;  and  in  case  of  accident  to  the  blower  it  is 
better  to  dump  the  cupola  at  once  than  to  attempt  to  hold  it 
for  any  length  of  time. 

Cupolas,  in  which  all  the  iron  charged  has  been  melted  and 
drawn  off,  may  be  held  over  night,  if  the  cupola  has  been 
properly  fluxed,  the  slag  drawn  off,  and  a  fresh  charge  of  coke 
put  in,  with  a  liberal  charge  of  limestone  on  top  of  it  to 
liquefy  any  slag  that  may  over  night  have  chilled  in  the  cupola. 
Small  cupolas  are  frequently  managed  in  this  way ;  the  tuyeres 
are  closed  and  the  tap  hole  permitted  to  remain  open  to  admit 
sufficient  air  to  ignite  the  fresh  coke. 

In  the  morning  after  the  cupola  has  been  rilled  with  stock 
and  the  blast  put  on,  the  limestone  on  the  bed  is  the  first  to 
melt,  and  if  in  sufficient  quantity  makes  a  fluid  slag  that 
settles  to  the  bottom,  freeing  the  cupola  of  any  clogging  that 
may  have  taken  place  during  the  stoppage. 

BANKING   A    CUPOLA. 

Since  writing  the  foregoing  paper  we  have  received  the  fol- 
lowing practical  illustration  of  keeping  a  cupola  in  good  con- 
dition for  melting  for  many  hours  after  it  had  been  charged 
and  the  blast  put  on,  from  Mr.  Knoeppel,  Foundry  Superin- 
tendent, Buffalo  Forge  Co.,  Buffalo,  N.  Y.  In  this  case  melt- 
ing had  not  begun  before  the  pulley  broke  and  the  blast  was 
taken  off,  but  the  same  results  would  have  been  obtained  from 
banking  the  cupola  in  this  way  if  melting  had  begun  and  the 
cupola  been  in  blast  for  a  short  time. 

"Banking  a  cupola  is  something  that  does  not  come  in  the 
usual  course  of  foundry  practice,  but  there  are  times  when  the 
knowledge  of  how  it  is  to  be  done  would  be  a  source  of  profit, 
as  well  as  loss  of  time  being  averted.  By  request  having  been 
induced  to  allow  this  letter  to  appear  in  your  valuable  publica- 


278  THE   CUPOLA   FURNACE. 

tion  on  »4  Cupola  Practice;'  hence  will  tryfand  give  you  the 
details  as  near  as  I  can  from  memory,  although  I  wrote  an  arti- 
cle on  this  subject  in  the  'American  Machinist,'  December  10, 
1891,  which  I  am  now  unable  to  get. 

"In  the  latter  part  of  October,  1891,  just  as  we  were  about  to 
put  on  the  blast  in  our  foundry  cupola  and  the  fan  making  a 
few  revolutions,  the  main  pulley  broke,  running  the  main  shaft 
to  the  fan  or  blower  of  our  cupola.  After  considerable  trouble, 
loss  of  time  and  delay  in  trying  to  get  a  new  pulley,  which  was 
of  wood  pattern,  we  finally  succeeded  in  getting  one  of  the 
proper  size,  and  had  it  put  on  the  shaft;  but  the  belt  being  a 
.little  tight,  and  also  anxious  to  get  off  the  heat,  in  .slipping  the 
belt  on  the  pulley,  it  was  cut  in  such  a  shape  that  it  became  use- 
less for  that  day.  By  this  time  it  was  beyond  our  regular  hour 
for  quitting.  At  first  there  seemed  no  way  out  of  the  dilemma 
but  to  drop  the  bottom.  The  thought  of  re-handling  the  hot 
material  and  fuel,  the  extra  labor. attached  therewith, suggested 
the  idea  of  holding  up  the  charges  until  next  morning,  when 
repairs  would  be  completed.  After  a  few  moments'  consulta- 
tion, proceeded  as  follows :  Let  me  say  first  that  the  cupolas 
was  lighted  at  I  :  45  p.  m.  and  at  6  p.  m.  began  the  operation 
of  banking  the  cupola,  having  had  four  hours  and  fifteen  min- 
utes' time  for  burning  the  stock,  and  being  charged  with  eleven 
tons  of  metal.  The  cupola  was  of  the  Colliau  type  60"  shell 
lined  to  44"  at  bottom  and  48"  at  melting  zone,  having  six 
lower  tuyeres,  7//x9//,  upper  tuyeres  being  closed.  Height  of 
tuyeres  from  bottom  when  made  up  18",  blast  pressure  10  oz., 
revolutions  of  blower  about  2100,  manufactured  by  the  Buffalo 
Forge  Co.,  and  known  as  No.  10,  the  adjustable  bed  type.  The 
cupola  bed  was  made  up  of  600  Ibs.  Lehigh  lump  coal  and  800 
Ibs.  Connellsville  coke,  the  succeeding  charges  50  Ibs.  of  coal 
and  150  Ibs.  coke,  coal  being  an  important  factor  in  this  heat 
on  account  of  its  lasting  qualities.  We  first  cleaned  and  cleared 
all  of  the  tuyeres,  packed  each  one  with  new  coke,  and  then  filled 
and  rammed  them  tight  with  floor  moulding  sand  to  prevent 
any  draft  getting  through  them,  and  had  the  top  of  charges 


TAKING   OFF   THE   BLAST   DURING   A    HEAT.  2/9 

covered  with  fine  coal  and  coke  dust,  and  tightened  that  also  to 
stop  the  draft  in  that  direction.  The  object  in  using  coal  dust 
was  this:  should  any  get  through  into  the  charges,  it  would  not 
cause  much  trouble.  After  all  was  completed,  gave  orders  to 
the  cupola  men  to  be  on  hand  at  6  a.  m.  next  morning,  clean 
out  the  tuyeres  and  top  of  cupola,  and  ordered  the  men  to  be 
ready  for  pouring  off  at  7  a.  m.  The  next  morning  all  were  on 
time.  I  had  the  tuyeres  poked  with  bars,  so  that  the  blast 
might  have  easy  access  to  center  of  cupola,  and  started  the 
blast  at  7 :  15,  bottom  being  dropped  at  8 :  45  ;  total  time  from 
time  of  lighting  cupola  until  bottom  dropped,  was  nineteen 
hours.  At  first  the  iron  was  long  in  coming  down  and  first  500 
Ibs.  somewhat  dull,  but  made  provision  for  that  and  put  it  into 
dies,  which  turned  out  to  be  very  good.  The  balance  of  the 
heat  was  hot  enough  for  any  kind  of  casting — our  line  being  light 
and  heavy,  and  had  to  be  planed,  bored  and  otherwise  finished 
with  some  stove  repair  casting  in  with  this  heat  engine  casting, 
cylinder  and  a  class  of  work  that  requires  fluid  metal.  I  am 
confident  that  if  this  method  is  carefully  followed,  it  can  be  done 
at  all  times,  but  would  not  advise  it  in  small  cupolas,  less  than 
36"  inside  measurement;  and  should  the  melt  be  in  progress,  it 
could  not  be  successfully  done  at  all.  Should  I  be  placed  in  a 
similar  position,  would  resort  to  the  same  means  with  more  con- 
fidence and  certainty  of  success. 

"Yours  respectfully, 

JOHN  C.  KNCEPPEL, 
Foundry  Supt.  Buffalo  Forge  Co.,  Buffalo,  N.  Y. 

BLAST  PIPES. 

In  constructing  a  cupola,  one  of  the  most  important  points  to 
be  considered  is  the  construction  and  arrangement  of  blast  pipes 
and  their  connection  with  the  cupola,  for  the  best  constructed 
cupola  may  be  a  complete  failure  through  bad  arrangement  of 
pipes  and  air-chambers. 

Not  many  years  ago  it  was  a  common  practice  of  foundry- 
men  to  place  blast  pipes  underground.  The  main  pipe  was 


280  THE   CUPOLA   FURNACE. 

generally  made  square  arid  constructed  of  boards  or  planks 
spiked  together,  no  care  being  taken  to  make  air-tight  joints, 
and  the  escape  of  blast  was  prevented  by  ramming  sand  or  clay 
around  the  pipe  when  put  in  place.  Connections  from  the 
main  pipe  to  the  cupola  were  made  by  means  of  vertical  cast- 
iron  pipes  to  each  tuyere,  as  shown  in  Figs.  31  and  32.  The 
main  pipes  were  generally  constructed  with  square  elbows  and 
ends,  and  the  tuyere  pipes  were  placed  over  an  opening  in  the 
top  of  a  branch  of  the  main  pipe  on  each  side  of  the  cupola.  The 
square  turns  and  ends  of  the  pipe  greatly  reduced  the  force  of 
the  blast,  and  the  capacity  of  the  pipe  was  frequently  reduced 
by  water  leaking  into  it  or  a  partial  collapse  of  the  pipe,  and 
the  volume  of  blast  delivered  to  a  cupola  was  very  uncertain 
even  when  the  pipes  were  new,  and  could  not  be  depended  upon 
at  all  when  the  pipes  became  old  and  rotten.  Iron  pipes  ar- 
ranged in  this  way  were  also  a  source  of  continual  annoyance 
and  uncertainty  from  water  or  iron  and  slag  from  the  tuyeres 
getting  into  them  and  reducing  their  capacity  for  conveying 
blast.  This  way  of  arranging  cupola  pipes  has  generally  been 
abandoned,  and  they  are  now  commonly  placed  overhead  or 
up  where  they  are  least  liable  to  injury  and  may  be  readily 
examined  to  see  that  there  is  no  leakage  of  blast  from  a  pipe. 
Blast  pipes  may  be  made  of  wood,  tin  plate,  sheet  iron,  cast 
iron,  or  galvanized  iron.  Wooden  pipes  shrink  and  expand 
with  changes  of  weather  and  moisture  in  the  atmosphere,  and  it 
is  almost  impossible  to  prevent  the  escape  of  blast  from  such 
pipes.  Tin  and  sheet  iron  pipes,  when  placed  in  a  foundry,  are 
very  rapidly  rusted  and  destroyed  by  steam  and  gases  escap- 
ing from  moulds  and  the  cupola,  if  not  thoroughly  painted  out- 
side and  in.  Cast  iron  pipes  are  heavy,  difficult  to  support  in 
place,  liable  to  break  when  not  properly  supported,  or  leak  at 
the  joints,  and  the  best  for  foundry  use  are  those  made  of  gal- 
vanized iron.  In  constructing  pipes  of  this  material,  an  iron  of 
a  proper  gauge  for  the  size  of  pipe  should  be  selected,  and  their 
shape  should,  whenever  possible,  be  round,  for  round  pipes  are 
more  easily  constructed  and  have  the  largest  effective  area  with 


TAKING   OFF   THE    BLAST   DURING   A   HEAT.  28 1 

a  given  perimeter  of  any  known  figure.  Pipes  should  be  made 
in  lengths  convenient  for  handling,  say  8  or  10  ft,  having  joints 
lapped  nearly  2  inches  in  direction  of  the  air  current.  Joints 
should  be  riveted  about  every  4  inches  to  hold  them  securely 
together  and  prevent  sagging  of  the  pipe  between  supports,  and 
to  insure  their  being  tight  they  should  be  soldered  all  the  way 
around.  Section  ends  should  be  placed  over  supports  and 
laps  of  from  3  to  4  inches  made  at  each  joint  and  also  soldered. 
The  end  of  the  main  pipe  when  not  connected  direct  with  an 
air  chamber  on  the  cupola  should  be  divided  into  two  or  more 
branches  of  equal  capacity  for  connection  with  the  tuyeres  or 
air  belt,  and  rounded  curves  or  elbows  used  in  changing  the 
direction  of  pipes.  A  pipe  should  never  terminate  abruptly, 
and  branches  should  not  be  taken  out  of  the  side  for  supplying 
the  cupola,  as  is  frequently  done.  The  area  of  main  pipes  and 
also  branch  pipes  should  be  increased  as  the  distance  from  the 
blower  to  the  cupola  is  increased  ;  and  as  a  guide  for  increasing 
their  diameter  in  proportion  to  the  length  of  pipe,  we  do  not 
think  we  can  do  better  than  give  our  readers  the  excellent 
table  prepared  by  the  Buffalo  Forge  Co.,  Buffalo,  N.  Y.,  as 
follows. 

DIAMETER    OF   BLAST   PIPES. 

It  will  be  seen,  by  reference  to  the  following  table,  that  the 
diameter  of  pipe  for  transmitting  or  carrying  air  from  one  point 
to  another,  changes  with  the  length  or  distance  which  the  air 
is  carried  from  the  blower  to  the  furnace,  or  other  point  of 
delivery. 

As  air  moves  through  pipes,  a  portion  of  its  force  is  retarded 
by  the  friction  of  its  particles  along  the  sides  of  the  pipe,  and 
the  loss  of  pressure  from  this  source  increases  directly  as  the 
length  of  the  pipe,  and  as  the  square  of  the  velocity  of  the 
moving  air. 

This  fact  has  long  been  known,  and  many  experimenters 
and  engineers,  by  close  observation  and  long-continued  experi- 
ments, have  established  formulas  by  which  the  loss  of  pressure 


282  THE   CUPOLA   FURNACE. 

and  the  additional  amount  of  power  required  to  force  air  or 
gases  through  pipes  of  any  length  and  diameter  may  be 
computed. 

As  these  formulas  are  commonly  expressed  in  algebraic 
notation,  not  in  general  use,  we  have  thought  it  desirable  to 
arrange  a  table  showing  at  a  glance  all  the  necessary  propor- 
tionate increase  in  diameter  and  length  of  blast  pipes  and 
conical  mouth-pieces,  in  keeping  up  the  pressure  to  the  point 
of  delivery.  It  is  often  the  case,  where  a  blower  is  condemned 
as  being  insufficient,  the  cause  of  its  failure  is  that  the  pipe 
connections  are  too  small  for  their  lengths,  coupled  with 
a  large  number  of  short  bends,  without  regard  to  making 
the  pipe  tight,  which  is  a  necessity. 

The  table,  diameter  of  pipes,  given  below,  showing  the 
necessary  increase  in  the  size  of  pipes  in  proportion  to  the 
lengths,  is  what  we  call  a  practical  one,  and  experience  has 
proved  the  necessity  for  it. 


TAKING   OFF   THE   BLAST    DURING   A   HEAT.  283 


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284  THE   CUPOLA   FURNACE. 

The  connection  of  blast  pipes  with  cupolas  is  also  a  matter 
to  which  entirely  too  little  attention  is  given,  and  is  frequently 
the  cause  of  poor  melting  when  cupola  is  otherwise  properly 
constructed.  As  stated  elsewhere,  tuyeres  should  be  large 
enough  to  admit  blast  to  a  cupola  freely,  and  to  obtain  good 
results  in  melting  it  must  be  fully  and  evenly  distributed  to 
the  tuyeres.  When  blast  is  delivered  direct  to  tuyeres  through 
branch  pipes,  the  branches  should  be  taken  off  the  main  pipe 
in  as  near  a  direct  line  with  the  current  of  the  blast  in  the 
mainpipe  as  possible,  and  its  course  to  the  tuyeres  should  be 
changed  by  long  curves  or  round  elbows  in  the  pipes,  to  pre- 
vent the  velocity  of  the  air  being  checked  and  blast  thrown 
back  in  the  pipe.  The  combined  area  of  all  the  branch  pipes 
should  be  equal  to  the  area  of  the  main  pipe  and  not  less  as  is 
frequently  the  case,  owing  to  a  mistake  being  made  through 
the  erroneous  idea  that  a  multiple  of  the  diameter  of  two  or 
more  small  pipes  is  equal  to  the  area  of  one  large  one  of 
their  combined  diameters.  If  this  were  the  case  two  five-inch 
pipes  would  have  an  area  equal  to  one  ten-inch  pipe,  which  is 
not  so,  as  will  be  seen  by  the  table  on  p.  285,  which  may  be  of 
value  to  foundrymen  in  arranging  their  blast  pipes. 


TAKING   OFF   THE    BLAST    DURING   A    HEAT. 

DIAMETER  AND  AREA  OF  PIPES. 


Diameter. 

Area. 

Diameter. 

Area. 

Diameter. 

Area. 

. 

2 

3.HI 

8^ 

53.456 

14)^ 

165.13 

2/4 

3-976 

8'/<2 

56.745 

!4^4 

170.85 

*3 

4.908 

8/4 

60.132 

1$ 

176.71 

2% 

5-939 

9 

63.617 

182.65 

3 

7.068 

9/4 

67.200 

15!^ 

188.69 

8.295 

9/^ 

70.882 

J5^4 

194.82 

3/2 

9.621 

9% 

74.662 

10 

201.06 

11.044 

10 

78.539 

16)4 

207.39 

4 

12.566 

I0>4 

82.516 

16^ 

213.82 

4/4 

14.186 

lO/lj 

86.590 

16^4 

220.35 

4^2 

15.904 

I0^4 

90.762 

17 

226.98 

4/4 

17.720 

ii 

95-033 

J7/4 

233.70 

s 

19.635 

I!/4 

99.402 

240.52 

21.647 

11  % 

103.86 

24745 

5/£ 

23.758 

n% 

108.43 

18 

25446 

6  4 

25.967 
28.274 

12 

113.09 
117.85 

Ily2 

261.58 
268.80 

6/4 

30.679 

12% 

122.71 

i&% 

276.11 

6)^ 

33.183 

I2/4 

127.67 

19 

283.52 

6% 

I3i 

132.73 

19)4 

291-03 

7 

38.484 

137-88 

IX 

298.64 

7/1 

41.282 
44.178 

13^ 

143.13 
148.48 

20 

306.35 
314.16 

l% 

47-173 
50.265 

14 
MH 

153.93 
159.48 

\ 

\ 

286  THE   CUPOLA   FURNACE. 

In  connecting  blast  pipes  direct  with  tuyeres,  either  by  long 
branch  pipes  from  the  main  pipe  or  short  ones  from  a  belt  air 
chamber  not  attached  to  cupola  shell,  care  should  be  taken  to 
have  as  few  joints  or  connections  in  the  pipes  as  possible,  and 
every  joint  should  be  made  in  such  a  way  that  the  jar  made  in 
chipping  out  and  charging  the  cupola  will  not  cause  the  joints 
to  leak  after  they  have  been  in  use  a  short  time.  In  leading 
pipes  out  of  an  air  chamber  they  cannot  always  be  placed  in 
line  with  the  current  of  the  blast,  and  must  be  filled  from  pres- 
sure of  blast  in  the  air  chamber,  but  the  connecting  pipes  may 
be  shaped  to  guide  the  blast  smoothly  from  the  air  chamber  to 
its  destination. 

In  Fig.  56  is  shown  as  perfect  a  connection  of  air  chambers 
of  this  kind  as  can  be  made.  In  this  illustration  the  belt  pipe 
A  A  is  placed  up  out  of  the  way  and  of  danger  of  being  injured 
when  making  up  or  working  the  cupola,  and  the  branch  pipes 
to  each  tuyere  are  straight  and  smooth  inside  and  the  pipe  is 
given  a  curve  at  the  bottom  to  throw  the  blast  into  the  tuyere 
without  having  the  force  of  its  current  impaired,  and  the  tuyeres 
are  of  a  size  to  admit  the  full  volume  of  blast  from  the  pipe. 
Only  two  joints  are  required  in  connecting  the  air  chamber  with 
the  cupola,  and  these  are  made  in  such  a  way  that  they  may  be 
securely  bolted  or  riveted,  and  all  leakage  prevented. 

In  contrast  with  the  neat  arrangement  of  pipes  on  this  cupola 
is  shown  the  other  extreme  of  poor  arrangement  in  illustration 
Figure  59.  This  is  a  section  of  a  "  perfect  cupola"  illustrated 
and  described  in  The  Iron  Age  some  years  ago,  and  while  other 
parts  of  the  cupola  may  have  been  perfect,  this  part  was  cer- 
tainly very  imperfect.  The  air  chamber  and  its  connecting 
pipes  are  made  of  cast  iron.  The  connecting  pipes  are  cast  in 
three  pieces,  necessitating  the  making  of  four  joints.  The  air 
box  is  cast  in  two  pieces,  requiring  another  joint;  and  a  peep- 
hole and  an  opening  for  escape  of  slag  and  iron  running  into 
the  tuyeres,  is  placed  in  the  pipe,  making  in  all  seven  joints  and 
openings  in  each  connection  to  be  made  and  kept  air-tight. 
The  jar  in  working  the  cupola,  together  with  the  small  explo- 


TAKING   OFF   THE   BLAST   DURING   A    HEAT.  287 

sions  of  gas  that  frequently  take  place  in  cupolas   and   pipes, 

FIG.  59. 


POOR  ARRANGEMENT  OF  BLAST  PIPES. 


would  naturally  tend  to  loosen  many  of  these  joints,  and  a  large 


288  THE   CUPOLA   FURNACE. 

amount  of  blast  would  be  lost  through  leakage  of  joints.  The 
many  joints  make  more  or  less  roughness  in  the  pipes,  thus  im- 
peding the  blast.  The  turn  in  the  pipe  for  connection  with  the 
tuyere  is  square  and  the  course  of  the  current  of  air  is  abruptly 
changed,  and  the  tuyere  is  entirely  too  small  to  admit  the  full 
volume  of  blast  from  the  pipe  to  the  cupola,  and  only  by  a 
heavy  pressure  of  blast  could  the  air  be  forced  into  the  cupola 
in  sufficient  quantities  to  do  good  melting. 

In -Fig.  57  is  shown  another  way  of  connecting  a  belt  air- 
chamber  with  the  tuyeres.  In  this  case  the  pipe  is  made  of 
galvanized  iron,  and  the  tuyere  boxes  are  made  of  cast-iron  and 
are  large,  giving  abundant  room  for  changing  the  direction  of  the 
blast  current.  Only  two  joints  are  made  in  connecting  the  air- 
chamber  with  the  cupola ;  beside  these  joints,  the  end  of  the 
tuyere  box  is  closed  with  a  large  door,  the  full  size  of  the  box, 
and  a  peep-hole  is  placed  in  the  door,  making  two  more  open- 
ings to  be  kept  air-tight.  Many  cupolas  are  in  use  having  their 
blast  connections  arranged  in  this  way,  and  while  the  arrange- 
ment is  very  good,  it  is  not  perfect,  and  a  great  deal  of  blast  is 
lost  through  leakage  of  joints — the  principal  loss  occurring 
around  the  large  door  and  at  the  joint  connecting  the  galvan- 
ized iron  pipe  with  the  cast-iron  tuyere  box. 

The  very  best  way  of  connecting  blast  pipes  with  cupola  tuy- 
eres is  by  means  of  a  belt  air-chamber  riveted  to  the  cupola  cast- 
ing, as  shown  in  Figs.  39,  43  and  45,  or  by  an  inside  air-chamber, 
as  shown  in  Figs.  3  I  and  46.  In  either  case  the  air-chamber  is 
riveted  to  the  cupola  shell  and  the  joint  made  perfectly  air-tight, 
and  in  case  of  jar  to  the  cupola,  the  air-chamber  being  part  of 
the  cupola,  oscillates  with  it,  and  the  jar  in  chipping  out  and 
charging  does  not  loosen  the  joint  and  cause  leakage  of  blast. 
The  blast  pipes  may  also  be  securely  riveted  or  bolted  to  the 
air-chamber  and  a  perfectly  tight  joint  made.  In  constructing 
cupolas  in  this  way,  care  should  be  taken  to  make  the  air- 
chamber  of  a  sufficient  size  to  admit  of  a  free  circulation  of 
blast  and  supply  all  the  tuyeres  with  an  adequate  amount  for 
good  melting.  When  the  air-chamber  is  small,  the  blast  pipe 


TAKING   OFF  THE  BLAST  DURING  A    HEAT. 


289 


should  be  connected  with  it  on  each  side  of  the  cupola,  and 
on  the  side  or  top  as  found  most  convenient.  When  the 
chamber  is  large  and  there  is  an  abundance  of  room  for  the 
escape  of  blast  from  the  pipe,  one  pipe  is  sufficient  and  it 
may  be  connected  on  the  side  or  top.  When  attached  on  the 
side  it  should  be  placed  in  line  with  the  circle  of  the  cupola  as 
shown  in  Fig.  48,  to  cause  the  current  of  blast  to  circulate 
around  the  cupola  and  facilitate  its  escape  from  the  pipe.  When 

FIG.  60. 


BLOWER   PLACED   NEAR    CUPOLA. 

the  current  of  blast  is  thrown  directly  against  the  cupola  casing 
or  bottom  of  the  chamber  in  a  narrow  air-chamber,  the  mouth 
of  the  pipe  should  be  enlarged,  to  facilitate  the  escape  of  blast 
into  the  chamber;  for  cupolas  of  this  construction  may  be  made 
a  complete  failure  by  failing  to  provide  a  sufficient  space  at  the 
end  of  the  pipe  for  escape  of  blast  into  the  air-chamber,  when 
the  chamber  is  of  a  sufficient  size  to  supply  the  cupola.  Con- 
nections with  the  inner  air-chambers  of  limited  capacity  should 
19 


2QO  THE   CUPOLA   FURNACE. 

be  made  on  each  side  by  means  of  an  air  or  tuyere  box  placed 
outside  as  shown  in  Fig.  6,  and  the  pipe  connected  on  top  to 
equalize  the  volume  of  blast  supplied  to  each  tuyere. 

Long  blast  pipes  often  cause  poor  melting,  from  the  volume 
of  blast  delivered  to  a  cupola,  being  reduced  by  friction  in  the 
pipes,  and  in  all  cases  the  blower  should  be  placed  as  near  the 
cupola  as  possible.  In  Fig.  60  is  shown  a  very  neat  arrange- 
ment in  placing  a  blower  near  a  cupola  and  at  the  seme  time 
having  it  up  out  of  the  way  of  removing  molten  iron  or  the 
dump  from  the  cupola,  and  the  space  under  it  may  be  utilized 
for  storing  ladles,  etc.  In  this  illustration  is  also  shown  a  very 
perfect  manner  of  connecting  the  main  pipe  with  an  air 
chamber.  The  pipe  is  divided  into  two  branches  of  equal 
size  in  line  with  the  current  of  blast  from  the  blower,  and  con- 
nected with  the  air  chamber  on  each  side  by  curved  pipes 
arranged  in  such  a  way  as  not  to  check  the  current  of  air  as  it 
passes  through  the  pipe. 

BLAST   GATES. 

These  devices  are  especially  designed  for  opening  and  clos- 
ing blast  pipes,  such  as  are  employed  for  conveying  air  be- 
tween blowers  and  cupolas.  There  are  several  different 
designs  of  blast  gates,  but  the  one  shown  in  Fig.  61  is  the  one 
most  commonly  used  by  foundrymen.  They  are  manufactured 
and  kept  in  stock  by  all  the  leading  manufacturers  of  blowers, 
and  cost  from  one  dollar  upwards,  according  to  size  of  blast 
pipe. 

The  employment  of  the  blast  gate  places  the  volume  of 
blast  delivered  to  a  cupola  under  control  of  the  melter,  which 
feature  is  frequently  very  important  in  the  management  of 
cupolas  in  melting  fron  for  special  work,  or  in  case  of  accident 
or  delay  in  pouring.  In  foundries  in  which  the  facilities  for 
handling  molten  metal  are  limited  and  melting  must  at  times 
be  retarded,  to  facilitate  its  removal  from  the  cupola  as  fast  as 
melted,  and  in  foundries  where  the  amount  of  iron  required  to 
be  melted  per  hour  is  limited  by  the  number  of  molds  or  chills 


TAKING    OFF   THE    BLAST   DURING   A   HEAT. 


291 


employed,  from  which  castings  are  removed  and  the  molds  re- 
filled, it  is  very  important  that  the  blast  should  be  under  con- 
trol of  the  melter.  In  such  foundries  the  cupolas  are  generally 
of  small  diameter  and  frequently  kept  in  blast  for  a  number  of 
hours  at  a  time,  and  it  is  often  desired  to  increase  the  volume 
of  blast  to  liven  up  the  iron  and  decrease  it,  to  reduce  the 
amount  melted  in  a  given  time. 

The  blast  gate  places  the  blast  under  control  of  the  melter 
and  enables  him  to  increase  or  diminish  its  volume  as  deemed 

FIG.  61. 


BLAST    GATE. 

necessary  to  obtain  the  best  results  in  melting.  They  are 
often  of  value  in  regular  cupola  practice  to  reduce  the  volume 
of  blast  and  retard  melting  for  a  few  minutes  while  pouring  a 
large  piece  of  work,  in  foundries  where  the  facilities  for  hand- 
ling large  quantities  of  molten  iron  are  limited,  and  the  speed 
of  blower  cannot  be  reduced  without  reducing  the  speed  of 
machinery  in  other  parts  of  the  works  or  stopping  the  blower 
entirely,  which  is  not  good  practise  after  a  cupola  has  been  in 
blast  for  some  time. 


292  THE   CUPOLA   FURNACE. 

The  gate  is  also  a  safeguard  against  gas  explosions,  which 
often  occur  from  the  accumulation  of  gas  in  pipes  during  the 
temporary  stoppage  of  the  blower.  The  gate  should  always 
be  placed  in  the  pipe  near  the  cupola,  and  closed  before  stop- 
ping the  blower  and  not  opened  until  it  is  again  started  up. 

EXPLOSIONS  IN  BLAST  PIPES. 

Violent  explosions  frequently  take  place  in  cupola  blast  pipes, 
tearing  them  asunder  from  end  to  end.  These  explosions  are 
due  to  the  escape  of  gas  from  the  cupola  into  the  pipes  during 
a  temporary  stoppage  of  the  blower  in  the  course  of  a  heat.  The 
explosion  is  caused  by  the  gas  being  ignited  when  the  pipe 
becomes  over-charged,  or  the  instant  the  blower  is  started  and 
the  gas  is  forced  back  into  the  cupola.  Such  explosions  gen- 
erally take  place  in  pipes  placed  high  or  arranged  in  such  away 
as  to  have  a  draught  toward  the  blower.  But  they  may  occur 
in  any  pipe  if  the  cupola  is  well-filled  when  a  stoppage  takes 
place  and  the  blower  is  stopped  for  a  great  length  of  time. 

Such  explosions  may  be  prevented  by  closing  the  blast  gate 
if  placed  near  the  cupola,  or  by  opening  the  tuyere  doors 
in  front  of  each  tuyere  and  admitting  air  freely  to  the  pipe. 
Such  precaution  should  always  be  taken  the  instant  the  blast  is 
stopped,  as  a  pipe  may  be  exploded  after  only  a  few  minutes' 
stoppage  of  the  blower,  and  men  may  be  injured  or  the  blower 
destroyed  by  the  explosion. 

BLAST  GAUGES. 

A  number  of  air  or  blast  gauges  have  been  designed  and 
placed  upon  the  market  for  determining  the  pressure  of  blast  in 
cupola  blast  pipes  and  air-chambers.  These  gauges  are  of  a 
variety  of  design,  and  are  known  as  steel  spring,  water  and  mer- 
cury gauges.  They  are  connected  with  a  blast  pipe  or  air- 
chamber  by  means  of  a  short  piece  of  gas-pipe  or  a  piece  of 
small  rubber  hose,  through  which  the  air  is  admitted  to  the 
gauge.  The  pressure  of  blast  is  indicated  by  a  face  dial  and 
hand  on  the  spring  gauge,  and  the  graduated  glass  tube  of  the 


TAKING   OFF  THE   BLAST   DURING  A   HEAT.  293 

water  and  mercury  gauges,  pressure  being  shown  up  to  two 
pounds,  in  fractions  of  an  ounce.  These  gauges,  when  in  good 
order,  indicate  very  accurately  the  pressure  of  blast  on  a  cu- 
pola, and  when  tuyeres  and  pipes  are  properly  arranged,  show 
to  some  extent  the  resistance  offered  to  the  free  escape  of  blast 
from  the  pipe  and  the  condition  of  the  cupola  in  melting.  But 
they  do  not  indicate  the  number  of  cubic  feet  of  air  that  pass 
into  a  cupola  in  any  given  length  of  time,  and  a  gauge  may 
show  a  pressure  of  six  or  eight  ounces  when  scarcely  a  cubic 
foot  of  air  is  passing  into  a  cupola  per  minute. 

With  a  pressure  blower  these  gauges  show  a  gradual  increase 
of  pressure  in  the  pipe  when  a  cupola  is  clogging  up,  and  may 
enable  a  foundryman  to  prevent  bursting  of  the  pipe  ;  but  with  a 
none-positive  blower  they  show  nothing  that  is  of  any  value  to 
a  foundryman  in  melting,  so  far  as  we  have  been  able  to  learn. 
The  volume  of  blast  is  what  does  the  work  in  a  cupola,  and  not 
the  pressure ;  and  a  high  pressure  of  blast  does  not  always  indi- 
cate a  large  volume  of  blast,  but  rather  the  reverse,  for  little  if 
any  pressure  can  be  shown  on  a  gauge  when  blast  escapes 
freely  from  a  pipe. 

We  have  seen  two  cupolas  of  the  same  diameter,  one  melting 
with  a  two-ounce  pressure  of  blast  and  the  other  with  a  six- 
ounce  pressure,  and  the  cupola  with  the  low  pressure  doing  the 
best  melting.  This  was  simply  because  with  the  low  pressure 
the  air  was  escaping  from  the  pipe  into  the  cupola  and 
with  the  high  pressure  it  was  not,  and  the  high  pressure  was 
wholly  due  to  the  smallness  of  the  tuyeres  which  prevented  the 
free  escape  of  blast  from  the  pipe  into  the  cupola. 

A  definite  number  of  cubic  feet  of  air  has  been  determined  by 
accurate  experiments  to  be  required  to  melt  a  ton  of  iron  in  a 
cupola,  and  an  air-gauge  to  be  of  any  value  in  melting  must  indi- 
cate the  number  of  cubic  feet  of  air  that  actually  enter  a  cupola 
at  the  tuyeres.  We  have  at  the  present  time  no  such  gauge, 
and  in  the  absence  of  such  a  gauge  the  foundryman's  best 
guide  as  to  the  number  of  cubic  feet  of  air  supplied  to  his 
cupola  is  the  tables  furnished  by  all  manufacturers  of  standard 


294  THE    CUPOLA    FURNACE. 

blowers,  giving  the  number  of  revolutions  at  which  their  blowers 
should  be  run,  and  the  number  of  cubic  feet  of  air  delivered  at 
each  revolution.  From  these  tables  a  foundryman  may  figure 
out  the  exact  number  of  cubic  feet  of  air  his  cupola  receives, 
provided  there  is  no  leakage  of  air  from  pipes  or  tuyeres  and 
the  tuyeres  are  of  a  size  that  will  permit  the  air  to  enter  the 
cupola  freely. 

BLAST    IN    MELTING. 

A  cupola  furnace  requires  a  large  volume  of  air  to  produce 
a  thorough  and  rapid  combustion  of  fuel  in  the  melting  of  iron 
or  other  metals  in  the  furnace.  Numerous  means  have  been 
devised  for  supplying  the  required  amount  of  air,  among  them 
the  draught  of  a  high  chimney  or  stack,  and  the  creating  of  a 
vacuum  in  the  cupola  by  means  of  a  steam  jet,  placed  in  a  con- 
tracted outlet  of  a  cupola  as  shown  in  Figs.  28  and  29.  These 
means  of  supplying  air  are  a  success  in  cupolas  of  small 
diameter,  and  limited  height,  but  even  in  these  cupolas  the 
volume  of  air  that  can  be  drawn  in  is  not  sufficient  to  produce 
rapid  melting,  and  it  is  doubtful  if  iron  could  be  melted  at  all 
in  a  cupola  of  large  diameter  and  of  a  proper  height  to  do 
economical  melting,  by  either  of  these  means  of  supplying  air. 
Owing  to  the  peculiar  construction  of  a  cupola  furnace  and  the 
manner  of  melting,  the  free  passage  of  air  through  it  is  re- 
stricted by  the  iron  and  fuel  required  ;  and  rapid  melting  can 
only  be  done  when  air  for  the  combustion  of  the  fuel  is  sup- 
plied in  a  large  volume,  which  can  only  be  by  a  forced  blast. 

A  number  of  machines  have  been  devised  for  supplying  this 
blast,  among  the  earliest  of  which  were  the  leather  bellows, 
trotnpe  or  water  blast,  chain  blast,  cogniardelle  or  water-cylin- 
der blast,  cylinder  or  piston  blower.  These  have,  as  a  rule,  given 
away  to  the  more  modern  fan  blower  and  rotary  positive  blast 
blower,  a  number  of  which  will  be  described  later  on. 

The  relative  merits  of  a  positive  aud  non-positive  blast,  is  a 
very  much  disputed  question.  It  is  claimed  by  many,  that 
with  a  positive  blast  a  definite  amount  of  air  is  supplied  to 
a  cupola  per  minute  or  per  hour,  while  with  a  non-positive 


TAKING   OFF  THE   BLAST   DURING  A    HEAT.  295 

blower  or  fan  there  is  no  certainty  as  to  the  amount  of  air  the 
cupola  will  receive.  This  is  very  true,  for  a  cupola  certainly 
does  not  receive  the  same  amount  of  air  from  a  fan  blower  when 
the  tuyeres  and  cupola  are  beginning  to  clog  as  it  does  from  a 
positive  blower  when  there  is  n^  slipping  of  the  belts.  But  is 
it  advisable  to  supply  a  cupola  with  as  large  a  volume  of  blast 
when  in  this  condition  as  when  working  open  and  free? 
Does  not  the  large  volume  of  blast  have  a  chilling  effect  upon 
the  semi-fluid  mass  of  cinder  and  slag,  and  tend  to  promote 
clogging  about  the  tuyeres  while  keeping  it  open  above  the 
tuyeres  ;  while  blast  from  a  non-positive  blower  would  perculate 
through  small  openings  in  the  mass,  and  be  more  effective  than 
a  large  volume  of  blast  from  a  positive  blower  forming  large 
openings  in  it  through  which  it  escaped  into  the  cupola? 

These  are  questions  we  have  frequently  tried  to  solve  by 
actual  test ;  but  it  is  so  difficult  to  find  two  cupolas  of  the  same 
dimensions  melting  the  same  sized  heats  for  the  same  class  of 
work,  one  with  a  positive  and  the  other  with  a  non-positive 
blast,  that  we  have  never  been  able  to  test  the  matter.  We  have 
melted  iron  with  nearly  all  the  blowers  now  in  use  and  with  a 
number  of  the  old-style  ones,  and  think  there  is  more  in  the 
management  of  a  cupola  than  there  is  in  a  positive  or  non- 
positive  blast.  Good  melting  may  be  done  with  either  of  them, 
when  the  cupola  is  properly  managed,  and  it  cannot  be  done 
with  either  of  them  when  the  cupola  is  not  properly  managed. 
Until  the  management  of  cupolas  in  every-day  practice  is  re- 
duced to  more  of  a  system  than  at  present,  it  will  be  impossible 
to  determine  any  practical  advantage  in  favor  of  either  blower 
over  the  other.  So  far  as  we  are  concerned,  we  have  no  prefer- 
ence in  blowers,  but  make  it  a  rule  to  charge  a  cupola  more 
openly  when  melting  with  a  non-positive  blast,  for  the  reason 
that  stock  may  be  packed  so  closely  in  a  high  cupola,  that  the 
volume  of  blast  that  is  permitted  to  enter  at  the  tuyeres  may 
not  be  reduced  by  preventing  its  escape  through  the  stock. 

The  amount  of  air  that  is  required  for  combustion  of  the  fuel 
in  melting  a  ton  of  iron  has  been  determined  by  accurate  ex- 


296  THE   CUPOLA   FURNACE. 

periments  to  be  about  30,000  cubic  feet,  in  a  properly  con- 
structed cupola  in  which  the  air  was  all  utilized  in  combustion 
of  the  fuel.  This  amount  of  air  if  reduced  to  a  solid  would 
weigh  about  24,000  Ibs.,  or  more  than  the  combined  weight  of 
the  iron  and  fuel  required  to  melt  it.  In  a  cupola  melting  ten 
tons  per  hour,  300,000  cubic  feet  of  air  must  be  delivered  to  the 
cupola  per  hour  to  do  the  work.  It  will  thus  be  seen,  that  a 
very  large  volume  of  blast  is  required  in  the  melting  of  10  tons 
of  iron.  To  deliver  this  amount  of  air  to  a  cupola  from  a 
blower  that  is  capable  of  producing  it  in  the  shape  of  a  blast, 
the  blast  pipes  must  be  arranged  in  such  a  way  that  the  velocity 
of  the  air  is  not  impeded  by  the  pipes ;  and  the  tuyeres  must 
be  of  a  size  to  admit  the  air  freely  to  the  cupola.  This  is  not 
always  the  case,  for  we  have  seen  many  cupolas  in  which  the 
combined  tuyere  area  was  not  more  than  one-half  that  of  the 
blower  outlet  The  object  in  making  the  tuyere  area  so  small 
was  to  put  the  air  into  the  cupola  with  a  force  that  would  drive 
it  to  the  center  of  the  stock.  This  was  the  theory  of  melting  in 
the  old  cupolas  with  small  tuyeres,  but  this  is  wrong,  for  air 
cannot  be  driven  through  fuel  in  front  of  a  tuyere,  as  an  iron 
bar  could  be  forced  through  it,  even  with  a  positive  blast ;  and 
when  the  air  strikes  the  fuel  it  cannot  pass  through  it,  but 
escapes  through  the  crevices  between  the  pieces  of  fuel.  These 
crevices  may  change  its  direction  entirely,  and  the  same  force 
that  drives  it  into  the  cupola  impels  it  in  the  direction  taken, 
which  will  be  the  readiest  means  of  escape,  and  is  more  liable 
to  be  up  along  the  lining  than  toward  the  center  of  the  cupola. 
For,  as  a  rule,  stock  does  not  pack  so  close  near  the  lining  as 
toward  the  center,  and  the  means  taken  to  prevent  the  escape 
of  blast  around  the  lining  is  the  very  thing  that  causes  it  to 
escape  in  that  way.  Since  blast  cannot  be  driven  through  fuel 
to  the  center  of  a  cupola  and  can  only  escape  from  the  tuyeres 
through  the  crevices  between  the  pieces  of  fuel,  the  only  way  to 
force  it  to  the  center  of  a  cupola  is  to  supply  a  sufficient  volume 
of  blast  to  fill  all  of  the  crevices  between  the  pieces  of  fuel. 
This  can  only  be  done  by  discarding  the  small  tuyeres  and 
using  a  tuyere  that  will  admit  blast  freely  to  a  cupola. 


TAKING   OFF  THE   BLAST   DURING   A   HEAT.  297 

In  placing  tuyeres  in  a  cupola,  it  must  be  remembered  that  the 
outlet  area  of  a  tuyere  is  governed  by  the  number  of  crevices 
between  the  pieces  of  fuel  in  front  of  the  tuyere  through  which 
the  blast  may  escape  from  the  tuyere.  With  small  tuyeres  a 
large  piece  of  fuel  may  settle  in  front  of  the  tuyere  in  such  a 
way  that  the  tuyere  outlet  is  not  equal  to  one  one-hundreth 
part  of  the  tuyere  area,  in  which  case  the  tuyere  is  rendered 
useless,  and  may  remain  useless  throughout  the  heat.  For 
these  reasons  small  tuyeres  should  never  be  placed  in  a  cupola. 
For  small  cupolas  we  should  recommend  the  triangular  tuyere, 
Fig.  14,  for  the  reason  that  it  tends  to  prevent  bridging,  and  its 
shape  is  such  that  it  is  less  liable  to  be  closed  by  a  large  piece 
of  fuel  than  a  round  tuyere  of  equal  area.  The  vertical  slot 
tuyeres,  Figs.  10  and  1 1,  are  also  for  the  same  reason  good  tuy- 
eres for  small  cupolas. 

For  large  cupolas  we  think  the  expanding  tuyere,  Fig.  3,  is 
the  best,  and  if  we  were  constructing  a  large  cupola  we  should 
use  this  tuyere  in  preference  to  any  other,  and  make  the  out- 
let at  least  double  the  size  of  the  inlet,  and  should  place  the  tuy- 
eres so  close  together  that  the  outlets  would  not  be  more  than 
six  or  eight  inches  apart.  This  would  practically  give  a  sheet 
blast,  and  distribute  air  evenly  to  the  stock  all  around  the 
cupola.  The  width  of  the  tuyere  can  be  made  to  correspond 
with  the  diameter  of  cupola,  and  may  be  from  three  to  six 
inches,  and  should  be  of  a  size  that  will  permit  blast  freely  to 
enter  the  cupola.  Parties  who  have  been  melting  with  small 
tuyeres  and  put  in  large  ones  upon  this  plan,  must  change  their 
bed  and  charges  to  suit  the  tuyeres,  for  this  arrangement  of 
tuyeres  would  probably  be  a  complete  failure  in  a  cupola  charged 
in  the  same  way  as  when  not  more  than  one-fourth  of  the  blast 
supplied  by  the  blower  entered  the  cupola. 

The  largest  cupolas  in  which  air  can  be  forced  to  the  center 
from  side  tuyeres  with  good  resnlts  would  appear  from  actual 
test  to  be  from  four  and  a  half  to  five  feet.  Larger  cupolas 
than  this  have  been  constructed,  and  are  now  in  use,  but  they 
do  not  melt  so  rapidly  in  proportion  to  their  size  as  those  of  a 


298  THE   CUPOLA   FURNACE. 

smaller  diameter.  To  illustrate  this,  we  might  cite  the  Jumbo 
Cupola  of  Abendroth  Bros.,  Port  Chester,  N.  Y.,  already  de- 
scribed, in  which  the  the  diameter  at  the  tuyeres  is  54  inches, 
and  above  the  bosh  72  inches,  in  which  1 5  tons  of  iron  have 
been  melted  per  hour  for  stove-plate  and  other  light  castings. 

The  Carnegie  Steel  Works,  Homestead,  Pa.,  have  cupolas  of 
seven  and  one-half  feet  diameter  at  the  tuyeres  and  ten  feet  di- 
ameter above  the  bosh,  in  which  the  best  melting  per  hour  is 
only  fourteen  tons.  The  area  of  this  cupola  at  the  tuyeres  is 
almost  three  times  that  of  Abendroth's  cupola,  yet  the  amount  of 
iron  melted  per  hour  is  actually  less  than  that  of  the  smaller 
cupola.  Tuyeres  have  been  arranged  in  different  ways  in  this 
large  cupola,  and  from  one  to  four  rows  used,  yet  the  melting  was 
not  in  proportion  to  the  size  of  cupola.  This  would  seem  to 
indicate  that  the  cupola  was  not  properly  supplied  with  blast 
near  the  centre,  and  the  melting  done  in  the  center  was  caused 
principally  by  the  heat  around  it ;  which  is  probably  the  case, 
for  the  cupola  is  kept  in  blast  night  and  day,  for  six  days,  and 
melting  must  take  place  in  the  centre,  or  the  cupola  would 
chill  up. 

There  are  many  cupolas  of  sixty  inches  diameter  at  the 
tuyeres  in  use  in  which  good  melting  is  done,  but  this  would 
seem  to  be  the  limit  at  which  good  melting  takes  place  in  a 
cupola  supplied  with  blast  from  side  tuyeres,  for  above  this  di- 
ameter the  rapidity  of  melting  does  not  increase  in  proportion 
to  the  increase  in  size  of  cupola. 

There  has  been  considerable  experimenting  done  during  the 
past  two  or  three  years  with  a  center  blast  tuyere  for  admitting 
blast  to  the  center  of  a  cupola  through  the  bottom.  We  have 
had  no  practical  experience  with  this  kind  of  tuyere  for  the  last 
twenty-five  years,  when  we  placed  one  in  a  small  cupola  with 
side  tuyeres  and  found  no  advantage  in  it;  probably  for  the 
reason  that  a  sufficient  quantity  of  air  for  an  even  combustion 
of  the  fuel  was  supplied  to  the  centre  of  the  cupola  from  the 
side  tuyeres. 

During  the  past  few  years,  we  have  visited  a  number  of  foun- 


TAKING   OFF  THE    BLAST   DURING   A    HEAT.  299 

dries  in  which  the  center  blast  was  being  tried,  but  in  every 
case  the  tuyere  was  out  of  order  or  not  in  use  at  the  time  of 
our  visit.  The  great  objection  to  this  tuyere  seems  to  be  its 
liability  to  be  filled  with  iron  or  slag  and  rendered  useless. 
Should  this  objectionable  feature  be  overcome  by  such  practical 
foundrymen  as  Mr.  West  or  Mr.  Johnson,  who  are  experiment- 
ing with  centre  blast,  it  would  certainly  be  a  decided  advantage 
in  melting  in  cupolas  of  large  diameter,  in  connection  with  side 
tuyeres.  In  cupolas  of  small  diameter  with  side  tuyeres,  we  do 
not  think  a  center  blast  would  increase  the  melting  capacity  of 
a  cupola,  for  the  reason  that  air  can  be  forced  to  the  center  of 
a  small  cupola  from  side  tuyeres,  when  properly  arranged  and 
of  a  proper  size. 

With  a  center  blast  alone,  it  is  claimed  that  considerable  sav- 
ing is  effected  in  lining  and  fuel.  It  is  reasonable  to  suppose 
that  a  saving  in  lining  might  be  effected  by  a  centre  blast;  for 
the  most  intense  heat  that  is  created  by  the  blast  is  transferred 
from  near  the  lining  to  the  center  of  the  cupola,  and  the  tend- 
ency to  bridge  is  greatly  reduced.  As  to  the  saving  of  fuel, 
there  never  was  a  new  tuyere  that  did  not  "save  fuel,"  and  there 
have  been  hundreds  of  them,  but  consumption  of  cupola-fuel 
is  still  too  large. 


CHAPTER  XXI. 

BLOWERS. 
PLACING   A    BLOWER. 

A  BLOWER  should  always  be  placed  at  as  near  a  point  to  a 
cupola  as  is  consistent  with  the  arrangement  of  the  foundry- 
plant,  and  it  should  be  laid  upon  a  good,  solid  foundation,  and 
securely  bolted  to  prevent  jarring,  as  there  is  nothing  that 
wrecks  a  blower  so  quickly  as  a  continual  jar  when  running  at 
high  speed.  In  Fig.  60  is  shown  a  convenient  way  of  placing 
a  blower  near  a  cupola,  aud  at  the  same  time  having  it  out  of 
the  way.  But  when  so  placed,  the  blower  should  be  laid 
upon  a  solid  frame-work  of  heavy  timber,  and  securely  bolted 
down  to  prevent  jarring  when  running.  It  should  also  be 
boxed  in  to  prevent  air  being  drawn  in  from  the  foundry,  and 
have  an  opening  provided  for  supplying  air  from  the  outside, 
for  air  drawn  from  a  foundry  when  casting  and  shaking  out  are 
taking  place  is  filled  with  dust  and  steam,  which  are  very  injur- 
ious to  a  blower  and  pipes. 

A  blower  should  never  for  the  same  reason  be  placed  in  a 
cupola-room  or  a  scratch  room  in  which  castings  are  cleaned ; 
for  it  is  impossible  to  exclude  dust  from  the  bearings  when  so 
placed,  and  when  a  bearing  once  begins  to  cut,  it  makes  room  for 
a  greater  amount  of  dust,  and  cuts  out  very  rapidly  in  blowers 
run  at  high  speed.  Dust  and  steam  also  corrode  and  destroy 
blast  wheels  which  are  inside  the  blower  and  out  of  sight,  and  a 
blast  wheel  may  be  almost  entirely  destroyed  and  not  discov- 
ered until  it  is  found  the  cupola  is  receiving  no  blast.  To  pre- 
vent a  blower  from  being  destroyed  in  this  way,  and  insure  a 
proper  volume  of  blast  for  a  cupola,  the  blower  should  be  placed 
in  a  clean,  dry  room  and  supplied  with  pure  air  from  the  outside. 

(300) 


BLOWERS.  3OI 

If  it  cannot  be  so  placed  near  a  cupola,  it  had  better  be  placed 
at  some  distance,  in  which  case  the  blast  pipe  must  be  enlarged 
in  proportion  to  its  length,  as  described  elsewhere.  When  a 
blower  is  placed  in  a  closed  room,  windows  should  be  opened 
to  admit  air  when  it  is  running,  and  when  the  air  about  the 
room  is  filled  with  dust,  a  pipe  or  box  for  supplying  pure  air 
should  be  run  off  to  some  distance  from  the  blower  and  the 
room  kept  tightly  closed. 

FAN  BLOWERS. 

BUFFALO  STEEL  PRESSURE  BLOWER.* 

The  manufacturers  make  claim  for  their  blower  as  follows ; 
In  Fig.  62  is  shown  the  latest  improved  construction  form  of 

FIG.  62. 


STEEL  PRESSURE  BLOWER. 


the  Buffalo  Steel  Pressure  Blower,  for  cupola  furnaces  and  forge 
fires.     A    distinguishing    feature    of   this  blower,    common  to 

*  Manufactured  by  Buffalo  Forge  Co.,  Buffalo,  N.  Y, 


302  THE    CUPOLA   FURNACE. 

those  of  no  other  manufacture  of  the  same  type,  is  the  solid 
case,  the  peripheral  portion  of  the  shell  being  cast  in  one  solid 
piece,  to  which  the  center  plates  are  accurately  fitted,  metal  to 
metal.  It  will  thus  be  seen  that  the  objectionable  and  slovenly 
"  putty  joint"  is  entirely  dispensed  with.  Ready  access  to  the 
interior  of  the  blower,  without  entirely  taking  it  apart,  is  also 
thus  afforded.  With  blowers  of  other  manufacture,  the  "  putty 
joint"  feature  of  the  shell  or  casing  is  an  indispensable  adjunct, 
although  it  is  a  construction  point  which  is,  at  the  best,  some- 
thing to  be  avoided  in  an  efficient  machine. 

The  Buffalo  Steel  Pressure  Blower  is  designed  and  con- 
structed especially  for  high  pressure  duty,  such  as  supplying 
blast  for  cupolas,  furnaces,  forge  fires,  sand  blast  machines,  for 
any  work  requiring  forcing  of  air  long  distances,  as  in  connec- 
tion with  pneumatic  tube  delivery  system.  It  is  adapted  for 
all  uses  where  a  high  pressure  or  strong  blast  of  air  is  re- 
quired. The  journals  are  long  and  heavy,  in  the  standard 
ratio  of  length  to  diameter  of  six  to  one,  and  embody  a  greater 
amount  of  wearing  surface  than  those  upon  the  blower 
of  any  other  construction.  Attention  is  directed  to  the  pat- 
ented journals  and  oiling  devices  employed  on  this  blower, 
which  are  unique  features.  The  bearings  are  readily  adjustable, 
and  any  wear  can  be  taken  up,  which  is  an  important  point  at- 
tending the  durability  and  quiet  running  of  a  perfect  machine. 

The  Buffalo  Steel  Pressure  Blower  possesses  the  fewest  number 
of  parts  of  any  like  machine ;  in  fact,  the  blower  is  practically 
one  piece,  so  that  under  any  service  the  bearings  invariably  are 
in  perfect  alignment,  vertically  and  laterally,  with  the  rest  of  the 
machine.  In  the  items  of  durability,  smooth  running  and 
economy  of  power,  it  is  thus  rendered  far  superior  to  any 
blower  with  the  so-called  universal  journal  bearing  which  is 
commonly  employed. 

In  every  point  of  construction,  the  greatest  pains  have  been 
taken  to  simplify  all  parts  and  at  the  same  time  to  give  them 
the  greatest  strength.  To  adjust,  repair  and  keep  in  order  a 
Buffalo  Blower  is  a  very  small  matter  and  readily  understood 
by  a  machinist  of  average  ability. 


BLOWERS.  303 

For  obtaining  the  best  results  from  a  blower  of  given  size, 
when  used  for  melting  iron  in  foundry  cupolas,  much  depends 
upon  the  proper  lay-out  of  the  blast  piping  between  the  blower 
and  the  cupola,  and  also  upon  the  proper  proportionment,  ar- 
rangement and  design  of  the  cupola  tuyeres,  Several  forms  of 
cupolas  are  now  upon  the  market,  economical  in  the  use  of  fuel 
and  fast  melting,  which  are  the  points  most  sought  for  in  cupola 
construction.  It  is  a  common  but  erroneous  idea  that  a  blower 
large  for  the  work  will  give  better  results,  in  a  given  diameter 
of  cupola,  than  a  smaller  one.  In  the  tables  which  accompany 
the  blower,  we  give  the  proper  sizes  of  blower  for  different 
diameters  of  cupolas ;  but  it  must  be  borne  in  mind,  that  if  the 
tuyerage  is  not  of  sufficient  area,  or  if  the  blower  has  to  be 
located  at  some  distance  from  the  work  to  be  accomplished, 
these  points  enter  for  consideration.  Frequently,  foundrymen, 
when  experiencing  difficulty  in  obtaining  satisfactory  melts, 
throw  the  whole  cause  of  the  trouble  upon  the  blower,  when 
the  fault  does  not  lie  at  this  point.  It  is  safe  to  say  that  failures 
are  due  more  largely  to  the  mismanagement  of  a  cupola  and 
improper  application  of  the  blower,  than  to  any  other  cause. 

The  Buffalo  Steel  Pressure  Blower  is  especially  adapted  for 
foundry  cupolas,  and  is  guaranteed  to  produce  stronger  blast 
with  less  expense  for  power,  than  any  other. 

BLOWER  ON  ADJUSTABLE  BED,  AND  ON  BED  COMBINED  WITH   COUNTERSHAFT. 

Unless  considerable  care  is  taken  in  putting  up  countershafts, 
and  some  special  attention  is  given  to  keep  them  in  perfect 
alignment,  trouble  is  often  experienced,  especially  in  keeping 
the  belts  on  the  larger  sizes  of  blowers,  on  account  of  the  great 
speed  at  which  they  have  to  run  to  produce  high  pressures.  To 
overcome  such  features,  this  house  designed  the  adjustable  bed, 
and  the  adjustable  bed  combined  with  countershaft  arrange- 
ments, which  is  illustrated  in  Fig.  63.  The  blower  on  adjust- 
able bed,  alone,  without  the  countershaft,  is  very  convenient 
for  taking  up  the  slack  in  belts  while  the  fan  is  in  motion  and 
driven  by  belt  from  main  line. 


304 


THE   CUPOLA   FURNACE. 


In  Fig.  63  is  shown  the  latest  construction  form  of  Buffalo 
Steel  Pressure  Blower  on  adjustable  bed  with  combined  counter- 
shaft. Its  use  will  be  found  to  result  in  a  decided  saving  in  the  wear 
and  tear  upon  belts,  which,  in  a  short  time,  more  than  justifies 
the  extra  initial  expense  of  the  arrangement.  The  cost  will  be 
found  little  in  excess  of  ordinary  method,  and  a  few  turns  of  the 
nut  on  the  end  of  the  adjusting  screw,  which  is  clearly  shown 
directly  under  the  outlet  of  the  blower,  after  first  unloosening 
the  holding- down  bolts,which  should  afterward  be  re-tightened, 

FIG.  63. 


BLOWER  AND  COUNTERSHAFT. 

accomplish,  in  a  very  few  moments,  what,  previous  to  the  intro- 
duction of  this  apparatus,  has  caused  considerable  delay  and 
annoyance.  It  will  readily  be  seen  that  the  usual  frequent  re- 
lacing  of  belts,  to  make  them  sufficiently  tight  to  avoid  slipping, 
is  hereby  entirely  obviated. 

Positive  alignment  of  the  countershaft  with  the  shaft  of  the 
blower  by  this  arrangement  causes  the  belt  to  track  evenly,  run 
smoothly  and  avoid  the  usual  wear  by  their  striking  against  the 
hanger  or  side  of  the  blower.  As  will  be  readily  appreciated, 
the  tightening  screw  gives  the  same  uniform  tension  to  both 


BLOWERS.  305 

belts,  and  this  may  be  regulated  at  will  of  operatior.  A  tele- 
.scopic  mouth-piece,  as  is  shown  by  the  cut,  is  placed  upon  each 
blower  purchased  in  this  form,  which  enables  the  machine  to 
be  moved  upon  its  bed  without  any  disarrangemnnt  of  the 
blast  piping. 

Especial  attention  is  called  to  the  fact  that  the  arrangement 
of  blower  on  adjustable  bed  combined  with  countershaft,  as  il- 
lustrated in  Fig.  63,  occupies  the  smallest  amount  of  space 
consumed  by  any  apparatus  of  this  kind  manufactured  in  the 
world.  Ordinary  tight  and  loose  pulleys  are  placed  upon  the 
countershaft  from  which  the  power  is  transmitted  to  the  counter- 
shaft of  this  apparatus.  When  this  feature  is  not  desirable, 
which  is  often  the  case  where  power  is  transmitted  from  the 
main  line  without  the  intervention  of  a  countershaft,  the  adjust- 
able bed  countershaft  may  be  furnished  with  the  blower,  so 
that  it  will  extend  at  the  right  or  left,  as  desired,  and  the  tight 
and  loose  pulleys  are  then  placed  thereon ;  we  then  have  a 
right  or  left  hand  apparatus.  The  space  between  the  two  pul- 
leys which  drive  the  blower  is  not  wide  enough  to  permit  of 
the  introduction  of  tight  and  loose  pulleys. 

BLOWER    ON    ADJUSTABLE    BED,    COMBINED   WITH    DOUBLE   UPRIGHT    ENGINE. 

We  would  call  attention  to  the  blower  in  the  adjustable  bed 
form  and  also  in  the  combination  with  countershaft.  The 
further  combination  as  secured  in  the  introduction  of  a  double 
upright  enclosed  engine  for  supplying  the  power,  affords  the  very 
highest  economy  and  convenience.  This  arrangement  gives 
positive  control  over  the  tension  of  belts,  ensures  the  greatest 
rigidity,  ease  in  adjustment,  perfect  alignment,  and 'when  it  is 
desirable,  an  immediate  change  in  the  speed  of  the  blower.  The 
latter  is  a  very  desirable  feature,  especially  in  cupola  work, 
because  in  hot  weather  it  requires  an  increased  volume  of  air  to 
melt  the  same  quantity  of  iron  over  that  of  cold  weather.  It 
will  readily  be  seen  that  this  arrangement  possesses  marked 
advantages  over  blowers  with  power  by  belt  transmission,  as 
they  may  be  run  whenever  desired,  and  are  independent  of 
other  sources  of  power. 
20 


306 


THE   CUPOLA   FURNACE. 


The  design  of  engine,  together  with  the  workmanship  and 
material  employed,  is  identically  the  same  as  upon  the  regular 
Buffalo  Double  Upright  Enclosed  Engine.  This  design  of  engine 
is  peculiarly  fitted  for  driving  steel  pressure  or  cupola  blowers. 
In  foundries  or  forge  shops,  much  dust  and  dirt  are  present  in 
the  atmosphere,  but  the  running  parts  of  the  engine  are  thor- 
oughly protected  therefrom.  As  will  be  seen  by  reference  to 
Fig.  64,  this  engine  is  furnished  with  a  common  oil  chamber 

FIG.  64. 


BLOWER  AND  UPRIGHT  ENGINE. 


on  top  of  frame,  from  which  oil  tubes  of  different  sizes,  accord- 
ing to  the  function  each  is  to  perform,  lead  to  every  recip- 
rocating part.  Continuous  running  is  possible  without  the  re- 
peated opening  and  closing  of  the  door  in  engine.  The  engine, 
which  is  built  in  a  variety  of  sizes  for  the  different  blowers,  being 
especially  designed  and  adapted  for  high  rotative  speed,  possesses 
short  stroke,  and  the  reciprocating  parts  are  perfectly  balanced. 

BUFFALO  ELECTRIC  BLOWER  BUILT  IN  "  B  "  AND  STEEL  PRESSURE  TYPES. 

The  "B"  Volume  Blower,  illustrated  in  Fig.  65  is  built  with 
electric  motors  of  approved  type  as  a  part  of  the  fan,  and  con- 
nected directly  to  the  fan  shaft.  Electric  fa'ns  afford  greater 


BLOWERS.  307 

convenience  even  than  direct  attached  engine  fans.  They  are 
unrivaled  in  their  adaptability  to  all  classes  of  work,  and  to  all 
locations.  To  start  and  stop  is  simply  a  matter  of  moving  a 
switch  or  pushing  a  button,  according  to  the  arrangement.  No 
engines  or  belts  are  required,  and  they  are  always  ready  for 
immediate  use. 

One  special  feature  of  their  great  convenience,  to  which  par- 
ticular attention  should  be  called,  is  the  fact  that  the  fans  can 
be  set  up  in  any  position  without  affecting  the  running  of  the 

FIG.  65. 


ELECTRIC  BLOWER. 


motor.  This  so  adapts  the  fans  that  they  may  be  located  to 
discharge  or  exhaust  from  any  desired  direction,  which  entails 
the  least  complication  of  pipe  connections.  The  "  B  "  volume 
type  of  blower  and  exhauster,  when  built  as  an  electric  fan,  can 
readily  be  furnished  in  the  different  styles  of  discharges  described 
for  this  design. 

All  types  of  fan  built  by  this  house  can  be  readily  fitted  and 
furnished  with  direct  attached  electric  motors,  though,  in  the 
case  of  very  large  steel  plate  fans,  it  is  usually  more  desirable  to 


308  THE   CUPOLA   FURNACE. 

employ  an  independent  motor,  conveniently  located,  and  then 
belt  to  the  fan.  All  the  fans  supplied  are  of  standard  high  grade, 
but  are  somewhat  especially  designed  to  receive  the  motors. 
That  the  highest  efficiency  may  be  secured,  electric  motors  of 
approved  design  and  special  construction  are  built  for  the  pro- 
pulsion of  the  different  varieties  of  fans.  They  are  also  capable 
of  continuous  use  with  only  ordinary  attention.  For  ventilating 
work,  these  fans  may  be  employed  in  a  multitude  of  positions 
where  the  introduction  of  an  engine  and  boiler  required  to  derive 
the  power  for  driving  other  varieties  of  fans  would  be  impossible. 
All  that  is  required  is  a  wire  connection  with  a  power  circuit, 
and  the  fan  is  ready  for  immediate  operation.  Electric  fans 
may  be  driven  at  a  high  speed,  therefore  they  are  of  large 
capacity.  The  combination  of  electric  motor  and  fan,  with 
proper  care  and  under  ordinary  conditions  of  use,  is  noiseless 
in  operation  and  is  the  acme  of  convenience. 

The  Buffalo  Steel  Pressure  Blower  is  frequently  furnished 
with  electric  motors  attached  direct  to  the  shaft.  It  is  desirable, 
especially  in  the  larger  sizes,  to  arrange  the  combination  of  steel 
pressure  blower  and  motor  substantially  as  shown  in  Fig.  65, 
substituting  the  motor  for  the  engine.  By  properly  proportion- 
ing the  pulleys  on  countershafts,  any  pressure  required  for  ordi- 
nary duty  can  be  given  while  the  motor  is  making  its  regular 
speed. 

BUFFALO  BLOWER  FOR  CUPOLA  FURNACES  IN  IRON  FOUNDRIES. 

In  the  following  table  are  given  two  different  speeds  and 
pressures  for  each  sized  blower,  and  the  quantity  of  iron  that 
may  be  melted  per  hour  with  each.  In  all  cases,  we  recom- 
mend using  the  lowest  pressure  of  blast  that  will  do  a  given 
work.  Run  up  to  the  speed  given  for  that  pressure,  and  regu- 
late the  quantity  of  air  by  the  blast  gate.  The  proportion  of 
tuyerage  should  be  at  least  one-ninth  of  the  area  of  cupola  in 
square  inches,  with  not  less  than  four  tuyeres  at  equal  distances 
around  cupola,  so  as  to  equalize  the  blast  throughout.  With 
tuyeres  one-twentieth  of  area  of  cupola,  it  will  require  double 


BLOWERS. 


309 


the  power  to  melt  the  same  quantity  of  iron,  and  the  blast  will 
not  be  so  evenly  distributed.  Variations  in  temperature  affect 
the  working  of  cupolas  very  materially,  Hot  weather  requires 
an  increase  in  volume  of  air  to  melt  same  quantity  of  iron  as  in 
cold  weather. 

TABLE  OF  SPEEDS  AND  CAPACITIES  AS  APPLIED  TO  CUPOLAS. 


8 

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666 

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717 

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2321 

773 

10 

4726 

2600 

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3244 

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4777 

1067 

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40 

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2948 

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2199 

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3310 

6082 

2469 

9 

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45 

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2785 

7818 

3203 

12 

3260 

8598 

3523 

10 

36 

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2195 

11295 

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5431 

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1797 

28019 

12736 

SMITH'S  DIXIE  FAN  BLOWER. 

This  blower  is  constructed  with  a  view  to  deliver  a  large  vol- 
ume of  air  under  moderate  pressure  with  the  least  possible  ex- 
penditure of  power.  It  is  the  nearest  to  noiseless  in  operation 
of  any  fan  blower  made,  and  is  of  the  simplest  and  strongest 
construction,  the  latest  design,  and  is  the  lightest  running  fan 
in  the  world.  It  has  steel  shafts,  wheels  and  casing,  and  is 
thoroughly  tested  and  fully  warranted.  The  construction  of  the 
case  or  shell  of  this  blower  is  entirely  different  from  anything 
heretofore  made,  and  owing  to  its  adjustable  hanger  bracket  and 
feet  on  all  four  sides,  it  is  adapted  for  any  possible  location 
or  position.  The  illustrations,  Figs.  66  and  67,  show  how  the 
blower  may  be  changed  from  bottom  to  top  horizontal  dis- 
charge, by  simply  turning  the  bearing  brackets  on  the  side  of 
blower  cases.  It  can  also  be  changed  to  bottom  or  top  vertical 


3io 


THE   CUPOLA   FURNACE. 


discharge  as  well,  in  less  than  five  minutes'  time,  by  simply 
loosening  four  bolts  on  either  side  of  the  blower  case  and  turn- 
ing the  bracket  one-fourth  round  either  way.  Tighten  up  again 
and  the  blower  is  changed  and  ready  for  operation  as  you  want 
it.  This  blower  is  adapted  to  cupola  furnaces  aud  forges,  and 
for  all  purposes  where  a  strong  blast  of  air  is  required,  or  a 
large  volume  of  air  such  as  is  needed  in  the  melting  of  iron  in 
foundry  cupolas,  for  which  purpose  a  large  number  of  these 

FIc.  66. 


Bottom  Horizontal  Discharge. 

SMITH'S  DIXIE  FAN  BLOWER. 

blowers  are  now  in  use.  The  proper  arrangement  of  pipes  in 
connecting  a  blower  with  a  cupola  is  a  matter  of  great  import- 
ance, if  the  full  volume  of  blast  from  the  blower  is  to  be  de- 
livered to  the  cupola.  The  friction  of  air  through  long  or 
crooked  pipes,  which  are  much  too  small  for  the  distance  the 
air  is  to  be  conducted,  or  the  pipes  having  one  or  more  short, 
abrupt  angles  between  blower  and  cupola,  is  often  the  cause  of 
much  annoyance  and  dissatisfaction,  and  frequently  blowers  of 


BLOWERS. 

all  makes  are  condemned  as  worthless,  when  the  piping  alone 
is  at  fault.  A  blower  delivering  air  two  hundred  and  fifty  feet 
from  the  blower  through  an  eight-inch  diameter  of  pipe,  the 
area  of  which  is  the  same  as  the  combined  area  of  the  tuyeres 
in  cupola,  will  not  deliver  over  two-thirds  the  pressure  at  the 

FIG.  67. 


Top  Horizontal  Discharge. 

SMITH'S  DIXIE  PAN  BLOWER. 


cupola  that  there  is  at  the  blower.  Under  like  conditions  a 
twelve-inch  diameter  of  pipe  would  deliver  15-16  of  the  pressure 
at  the  blower  to  the  cupola.  Built  by  the  American  Blower 
Co.,  Detroit,  Michigan. 


FORCED  BLAST  PRESSURE  BLOWERS. 
THE  MACKENZIE  BLOWER. 

In  Fig.  68  is  shown  a  section  of  the  Mackenzie  Positive  or 
Pressure  Blower,  which  is  probably  the  first  rotary  positive 
blower  introduced  in  this  country,  and  is  certainly  the  first  one 


312 


THE   CUPOLA   FURNACE. 


to  come  into  general  use  for  foundry  cupolas.  This  blower  was 
designed  by  the  late  P.  W.  Mackenzie  and  introduced  in  con- 
nection with  the  Mackenzie  cupola,  and  was  a  decided  improve- 
ment upon  the  rotary  fan  blower  then  in  common  use.  The 
blower,  although  an  old  one,  is  said  by  those  who  have  used  it 
to  be  a  good  one,  and  a  large  number  are  at  the  present  time 
in  use  in  foundries  in  various  parts  of  the  country.  A  descrip- 
tion and  claims  for  the  blower  are  furnished  by  its  present 

FIG.  68. 


SECTION  OF  MACKENZIE  BLOWER. 

manufacturers,  Isbell  Porter  Co.,  46  Bridge  St.,  Newark,  N.  J., 
as  follows : 

It  is  a  well-known  fact  that  a  trustworthy  blast,  thoroughly 
penetrating  the  charge,  is  of  the  utmost  importance  in  the 
economical  working  of  a  cupola,  saving  in  many  instances  twenty 
to  thirty  per  cent,  of  coal.  The  Mackenzie  blower  is  a  positive 
or  pressure  blower,  that  is,  it  delivers  a  definite  quantity  of  air 
for  each  revolution,  regardless  of  the  condition  of  the  cupola. 
This,  of  course,  is  essential  to  the  proper  melting  of  iron.  It 


BLOWERS. 


313 


requires  less  speed,  has  the  least  possible  friction  of  parts,  and 
consequently  uses  less  power  than  any  other  blower  made.  The 
late  P.  W.  Mackenzie  in  experiments  with  blowers  found  that 
no  positive  blower  required  more  than  six-tenths  of  the  power 
required  for  the  best  fan  blowers,  when  the  pressure  exceeded 
four-tenths  of  a  pound  per  square  inch. 

This  blower  is  practically  noiseless  in  operation,  and  fts  dura- 
bility is  unequaled. 

We  build  eight  sizes : 


No. 

Dia.  of  Shell. 

Capacity  per 
100  revolutions. 

Size  of  Outlet 
Opening. 

Floor  Space 
occupied. 

Price. 

3 

22" 

1300  cu.  ft. 

9K"  x  13^" 

58"  x  36" 

4 

32 

1800 

10        x  i8>£ 

71     x    " 

1 

48 
« 

3200 
4500 

12%      X  19^ 
13            X25 

70    X54 
82    x   " 

7 

« 

5600 

"        x  36>2 

94    x   " 

8 

60 

7500 

19}^    x  24 

96    x75 

9 

« 

10000 

X26 

108    x   « 

10 

« 

12500 

"         x  27^ 

120     X    " 

No.  3  will  supply  blast  for  No.  i  and  No.  2  MACKENZIE  CUPOLA  with  2  to  3  H.  P. 
«    4        «  «  No.  3  "  "          "     3  "  4    " 

«    5         "  "    No.  4  and  No.  5  "  "  "     4  "  5     " 

«    6        "  "    No.  6    "    No.  8  "  "          "     6  «  7    " 

It  will  melt  faster  and  with  less  power  in  straight  cupolas 
than  any  other  blower  in  use. 

No.  3  will  supply  blast  for  Cupolas          to     30"  dia.  with  3      to  3)^  H.  P. 
«    4         «  «  «         ipii  tt      ^6"     "      "     3%  "  5          " 

U      5  «  »  a  36       „        4g          „         «       5          u    7 

<«    6        "  "  "        48     "      60       "      "7      "8         " 

The  construction  and  operation  of  the  machine  will  be  readily 
understood  from  the  cut.  The  blades  are  attached  to  fan  boxes, 
which  revolve  on  a  fixed  center  shaft.  Motion  is  imparted  to 
them  by  means  of  a  cylinder  to  which  are  attached  the  driving 
pulleys.  Half-rolls  in  the  cylinder  act  as  guides  for  the  blades, 


3  14  THE   CUPOLA   FURNACE. 

allowing  them  to  work  smoothly  in  and  out  as  the  cylinder  re- 
volves. At  each  revolution  the  entire  space  back  of  the  cylinder 
between  two  blades  is  filled  and  emptied  three  times. 

DIRECTIONS  FOR  SETTING  UP  BLOWER. 

Set  the  machine  upon  a  level  and  substantial  foundation,  in  a 
room  free  from  dust.  The  main  pipe  should  be  equal  in 
capacity  to  the  combined  capacity  of  the  tuyere  pipes. 

For  blowers  Nos.  3  and  4,  the  diameter  of  main  pipe  should 
be  thirteen  to  fifteen  inches,  and  for  Nos.  5  and  6,  the  diameter 
of  main  pipe  should  be  from  sixteen  to  eighteen  inches ;  all 
connections  must  be  permanently  air-tight,  and  all  curves  made 
easy.  The  blades  should  be  oiled  freely  for  a  few  days,  then 
they  will  show  plainly  where  oil  should  be  used.  The  shaft 
upon  which  the  fan  boxes  revolve  is  hollow,  and  the  opening  to 
the  oil  passage  in  shaft  will  be  seen  outside  the  hanger  and  on 
top  of  shaft.  Fill  the  shaft  with  oil  when  the  machine  is  started, 
and  supply  a  small  portion  occasionally  when  running.  Keep 
the  passages  open  so  that  the  oil  will  find  its  way  readily  to  the 
bearings.  Use  good  oil,  give  the  machine  proper  care,  and  it 
will  last  for  years  without  repairs. 

THE  GREEN  PATENTED  POSITIVE  PRESSURE  BLOWER. 

This  is  a  blower  of  a  new  design  recently  placed  upon  the 
market  by  the  Wilbraham-Baker  Blower  Co.,  Philadelphia,  Pa., 
to  take  the  place  of  the  Baker  blower,  for  many  years  manu- 
factured by  them.  The  new  blower  is  said  to  be  a  great  im- 
provement upon  the  Baker  blower,  which  is  one  of  the  best  in 
use  for  foundry  cupolas.  Claims  for  the  Green  blower  are  made 
by  the  manufacturers  as  follows : 

This  blower  is  designed  to  occupy  the  minimum  space,  dis- 
place the  largest  volume  for  the  space  occupied,  exhaust  and 
deliver  in  a  practically  even  volume,  have  the  least  weight  com- 
bined with  ample  strength,  be  entirely  void  of  complications, 
complicated  shapes,  sliding  parts  or  sliding  motion,  the  least 
liability  to  get  out  of  order,  the  least  weight  to  revolve,  be  en- 


UNIVERSITY 


Or 


BLOWERS. 


315 


tirely  free  of  internal  friction  in  case  of  wear  of  the  journals,  and 
do  the  work  with  the  minimum  power. 

The  working  parts  are  two  perfectly  balanced  impellers,  each 
of  which  is  a  single  strong  casting,  well  ribbed  inside  and  firmly 
fastened  to  a  steel  shaft  of  ample  dimensions,  extending  the  full 
length  of  blower,  the  shaft  being  flattened  where  it  passes 
through  the  body  of  impeller. 

The  journal  bearings  are  bushed  with  phosphor  bronze  and 
are  detachable  from  blower,  being  bolted  and  dowel  pinned  to 

FIG.  69. 


SECTIONAL  VIEW. 


the  head  plate,  easily  removed  and  returned  to  their  original 
central  position. 

The  blower  is  geared  at  both  ends,  the  gearing  being  of 
ample  proportions,  cut  in  the  most  accurate  manner,  and  en- 
closed in  an  oil-tight  cover,  free  from  dust  and  dirt,  and  con- 
tinuously in  oil.  The  case  of  blower  is  well-proportioned, 
strongly  ribbed  and  firmly  bolted  together. 

The  head  plates,  in  addition  to  being  well-ribbed,  are  further 
strengthened  by  having  the  hoods  or  extensions,  into  which 
the  circular  ends  of  the  impellers  project,  a  part  of  head-plate 
casting. 


3l6  THE   CUPOLA   FURNACE. 

The  circular  parts  of  casing  and  the  pipe  plates  are  also  ribbed, 
and  the  pipe  plates  are  fitted  in  between  and  bolted  to  the  head 
plates  and  circular  casing. 

The  finished  surfaces  of  the  impellers  are  two  circles,  which 
roll  together  without  friction,  forming  an  even  and  continuous 
practical  contact;  the  point  of  contact  being  always  on  the 
pitch  line  of  the  gears  and  traveling  at  the  same  speed  at  all 
points  of  the  revolution. 

The  gear  wheels  are  keyed  to  the  shafts  close  to  ends  of 
journal  bearings,  forming  collars  at  each  end  of  blower,  prevent- 

FIG.  70. 


COMPLETE  IMPELLER. 

A  single  casting  with  Steel  Forged  Shaft  in  position.     Two  such  pieces  compose  the  interior  working 
parts  of  Blowers  and  Exhausters. 

ing  the  impellers  from  rubbing  endwise  against  the  interior 
sides  of  head  plates. 

These  provisions  insure  an  entire  absence  of  internal  friction 
at  all  times,  and  are  a  positive  preventive  of  possible  accidents. 

The  following  Fig.  (71)  shows  Standard  Green  Blower  with 
discharge  outlet  on  either  side.  Fig.  69  a  sectional  view,  and 
Fig.  70  the  complete  impeller. 

The  inlet  and  outlet  flanges  are  tapped  for  tap  or  screw  bolts 
and  provided  with  loose  flanges  for  attaching  light  sheet-iron 
pipe. 

Directions  for  setting  up. — Set  the  blower  perfectly  level  and 
solid.  Brick  or  stone  is  best  for  a  foundation  ;  timber  is  liable 
to  rot  and  allow  blower  to  get  out  of  level.  See  that  oil  holes 


BLOWERS. 


317 


are  clean  before  attaching  oil  cups,  and  set  cups  to  feed  prop- 
erly. Before  attaching  pipes  see  that  nothing  has  fallen  into 
the  blower.  Fasten  a  coarse  wire  screen  on  end  of  inlet  pipe. 
Wipe  the  gear  wheels  and  gear  casing  perfectly  clean  before 
attaching  the  casing,  and  cover  the  joint  between  parts  of  gear 
casing  with  red  or  white  lead.  Put  a  supply  of  good  heavy  oil 
inside  the  gear  covers,  say  a  pint  in  each  small,  and  a  quart  in 
each  large  cover,  and  draw  off  this  oil  and  replace  with  fresh  oil 

FIG.  71. 


STANDARD  GREEN  BLOWER. 


about  once  each  month.     Use  a  good  fluid  oil  on  journals  and 
gear-wheels.     No  lubricant  required  inside  of  blower. 

Efficiency  of  blower. — The  blower  is  not  guaranteed  to  ac- 
complish any  given  duty;  the  blower  simply  furnishes  the  air 
at  its  discharge  outlet ;  the  result  obtained  depending  upon  the 
disposition  of  the  air  after  it  leaves  the  blower.  Tight  iron 
pipes  must  be  used  so  that  all  the  air  delivered  by  the  blower 
will  reach  the  desired  point.  For  overground,  galvanized  iron 
pipes,  riveted  and  soldered,  are  good,  and  for  underground,  cast 
iron  is  the  best.  Cast  iron  blast  gates  are  recommended.  Light 


318  THE    CUPOLA   FURNACE. 

wrought  iron  or  brass  gates  are  liable  to  leak  and  impair  the 
efficiency  of  the  blower.  A  blast  gate  having  the  gate  pass  en~ 
tirely  through  the  frame  is  the  best. 

Power. — For  estimating  the  approximate  amount  of  power 
required  to  displace  a  given  amount  of  air  at  a  given  pressure, 
it  is  customary  to  add  25  per  cent,  to  the  net  result  obtained  by 
using  the  following  rule.  Rule. — Multiply  the  number  of  cubic 
feet  delivered  per  minute  by  the  pressure  in  ounces  per  square 
inch  (at  the  blower)  and  the  product  by  .003  ;  divide  the  last 
amount  by  1 1. 


BLOWERS. 


319 


u 


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320  THE   CUPOLA   FURNACE. 

SPEED   OF   FOUNDRY   BLOWERS. 

No.  I  blower  displaces  3  cubic  feet  per  revolution.  Suitable 
for  cupola  24  to  28  inches  diameter  for  melting: 

%  tons  per  hour 125  revolutions  per  minute. 

1 1^     "  "        210          "  " 

\%     «          "        290 

No.  2  blower  displaces  5^  cubic  feet  per  revolution.  Suit- 
able for  cupola  24  to  34  inches  diameter,  for  melting : 

i%  tons  per  hour 115  revolutions  per  minute. 

2%     "  "        230  "  " 

3        "          "        275 

No.  3  blower  displaces  9  cubic  feet  per  revolution.  Suitable 
for  cupola  28  to  40  inches  diameter,  for  melting: 

2  tons  per  hour no  revolutions  per  minute. 

3  "  "        165 

^A    "        "      245 

No.  4  blower  displaces  15  cubic  feet  per  revolution.  Suitable 
for  cupola  32  to  45  inches  diameter,  for  melting: 

3  tons  per  hour 100  revolutions  per  minute. 

5  «  «        170          "  " 

6)£      «  "  220 

No.  4^  blower  (small  No.  5),  displaces  20  cubic  feet  per 
revolution.  Suitable  for  cupola  36  to  50  inches  diameter,  for 
melting : 

4  tons  per  hour 100  revolutions  per  minute. 

6  "          "        150          "  " 

9        "          "        225          "  " 

No.  5  blower  displaces  25  cubic  feet  per  revolution.  Suit- 
able for  cupola  42  to  56  inches  diameter,  for  melting: 

5  tons  per  hour 100  revolutions  per  minute. 

8         "  "        160 

10        "  "        200  "  " 

No.  5*^  blower  (small  No.  6),  displaces  35  cubic  feet.  Suit- 
able for  cupola  48  to  64  inches  diameter,  for  melting : 


BLOWERS.  321 

8  tons  per  hour  ......................  115  revolutions  per  minute. 

i°         "  "        ..............  •  .......  145 

14  "  "        ......................  200          "  " 

No.  6  blower  displaces  42  cubic  feet  per  revolution.  Suit- 
able for  cupola  50  to  70  inches  diameter,  for  melting: 

9  tons  per  hour  ......................  no  revolutions  per  minute. 

12         "  "        ......................  145  "  « 

15  "          "        ......................  180          "  " 

No.  7  blower  displaces  67  cubic  feet  per  revolution.  Suit- 
able for  cupola  66  to  78  inches  diameter,  or  two  cupolas  48  to 
56  inches  diameter,  for  melting: 

14      tons  per  hour  ......................  105  revolutions  per  minute. 

18        "  "        ...........   ..........  135  "  " 

20        "  "        ......................  150          "  " 

No.  8  blower  displaces  112  cubic  feet  per  revolution.  Suit- 
able for  cupola  74  to  92  inches  diameter,  or  two  cupolas  54  to 
66  inches  diameter,  for  melting  : 

20      tons  per  hour  .....................   90  revolutions  per  minute. 

25^     "  "        .....................    115  "  " 

30        "  "        ......................  135  "  " 


No.  7J^  blower  displaces  85  cubic  feet  per  revolution. 
No.  9  blower  displaces  200  cubic  feet  per  revolution. 

Speed.  —  For  blowers  running  continuously  at  pressures  of 
about  two  pounds  per  square  inch,  the  following  maximum  speed 
is  recommended  : 

No.  of  blower  .....................   I       2       3      4    4}^     5     53^     678 

Revolutions  per  minute  .............  250  250  225  200  200  175  175  150  135  100 

Displacement  per  rev.  in  cubic  feet  ...   3     5)^     9      15     20     25     35     42     67    112 

CONNERSVILLE  CYCLOIDAL  BLOWER. 

The  Connersville  Positive  Pressure  Blower,  manufactured  by 
the  Connersville  Blower  Co.,  Connersville,  Ind.,  is  one  of  the 
latest  designs  of  blower,  and  has  only  been  manufactured  for  a 
few  years.  A  description  of  it  is  taken  from  the  excellent  cir- 
cular which  is  well  worth  reading  by  those  contemplating  the 
purchase  of  pressure  blowers,  and  is  as  follows  : 

21 


322  THE    CUPOLA   FURNACE. 

The  cycloidal  curves,  their  nature,  peculiarities  and  possi- 
bilities, have  always  been  an  attractive  study,  not  only  to  the 
theoretically  inclined,  but  more  particularly  to  those  interested 
in  the  many  important  applications  of  these  curves  in  practical 
mechanics.  The  especial  value  of  combining  the  epi-  and  hypo- 
cycloids  to  form  the  contact  surfaces  of  impellers  for  rotary 
blowers,  gas  exhausters  and  pumps  has  long  been  recognized, 
and  many  attempts  have  been  made  to  utilize  them  in  that  con- 
nection, but  in  vain.  While  conceded  to  give  the  theoretically 
correct  form  to  a  revolver  or  impeller,  it  came  to  be  regarded 
as  impossible  to  produce  such  surfaces  by  machinery  with  suffi- 


SECTIONAL  VIEW  OF  CONNERSVILLE  CYCLOIDAL  BLOWER. 

cient  accuracy  to  admit  of  their  use  in  practice  with  any  degree 
of  satisfaction.  It  remained  for  us  to  demonstrate  that  it  could 
be  done,  and  in  a  highly  successful  manner  as  well. 

Fig.  72  is  an  illustration  showing  a  cross  section  of  our  new 
cycloidal  blower,  and  particularly  of  the  revolvers  or  impellers, 
their  form,  relation  to  each  other,  and  to  the  surrounding  case. 
A  glance  only  is  required  to  discern  the  superiority  of  this 
method  of  construction  over  all  others. 

The  vital  part  of  every  machine  of  this  class  is  the  impeller, 
as  on  it  depend  economy  of  operation  and  efficiency  in  results. 


BLOWERS.  323 

That  we  have  the  ideal  form  for  an  operating  part  is  self-evident. 
It  will  be  noted  that  there  are  two  impellers  only,  and  each  is 
planed  on  cycloidal  lines  with  mathematical  accuracy.  Now,  it 
is  one  of  the  well-known  peculiarities  of  the  epi-cycloidal  and 
hypo-cycloidal  curves,  when  worked  together  as  in  our  machines, 
that  there  is  a  constantly  progressive  point  of  contact*  between 
the  impellers.  As  a  result  of  this  regular  advance  of  the  point 
of  contact,  the  air  is  driven  steadily  forward,  producing  a  smooth 
discharge  that  is  conducive  to  the  highest  economy. 

The  advantage  of  this  arrangement  over  the  use  of  arcs  of 
circles  to  approximate  contact  curves  is  very  great,  as  it  is  a 
well-demonstrated  fact  that  circular  arcs  whose  centers  are  not 
co-incident  with  the  centers  of  revolution  can  not  keep  practical 
contact  through  an  angle  of  more  than  four  or  five  degrees.  On 
the  contrary,  the  contact  does  not  progress  continuously,  but 
jumps  from  one  point  to  another  across  intervening  recesses  as 
the  impellers  revolve,  leaving  pockets  in  which  the  air  is  alter- 
nately compressed  and  expanded,  producing  undesirable  pulsa- 
tions in  the  blast,  a  waste  of  power,  and  necessitating  two  points 
of  contact  at  one  time  in  four  positions  in  each  revolution. 

Another  advantage  of  the  cycloidal  form  is  that,  at  the  point 
of  contact,  a  convex  surface  is  always  opposed  to  a  concave 
surface ;  that  is,  the  epi-cycloidal  part  of  one  impeller  works 
with  the  hypo-cycloidal  part  of  the  opposite  impeller.  The  con- 
sequence of  this  is  to  produce  a  long  contact  or  distance  through 
which  the  driven  air  must  travel  to  get  back  between  the  im- 
pellers, instead  of  the  short  contact  that  results  when  two  con- 
vex surfaces  oppose  each  other,  as  is  the  case  in  other  machines 
of  this  character. 

Attention  has  previously  been  directed  to  the  fact  that  the 

*  Wherever  the  expression  "  point  of  contact "  is  used  in  this  description,  it  must 
not  be  understood  to  mean  that  the  impellers  actually  touch  at  such  points,  but  that 
it  is  the  point  of  nearest  approach.  In  practice  it  has  been  found  advisable  to  allow 
a  very  slight  clearance  rather  than  have  the  parts  rub  together,  as  thereby  friction  and 
wear  are  entirely  eliminated,  while  on  account  of  the  "  long  contact "  referred  to,  the 
leakage  is  insignificant.  Our  method  of  planing  the  impellers  enables  us  to  make  the 
clearance  very  slight. 


324  THE   CUPOLA   FURNACE. 

point  of  contact  between  the  impellers  continuously  progresses  ; 
indeed,  the  path  it  describes  is  a  circle.  One  result  of  this  con- 
tinuously-progressive contact,  as  before  mentioned,  is  a  smooth, 
reliable  blast.  Another  is,  as  has  also  been  noted,  the  absence 
of  any  pockets  or  cavities  in  which  air  can  be  gathered,  com- 
pressed and  then  discharged  back  toward  the  inlet  side  of  the 
machine,  thereby  entailing  a  waste  of  power  and  shortening  the 
life  of  the  blower  by  subjecting  the  impellers,  shaft  and  gears  to 
a  needless  shock,  strain  and  wear.  Furthermore,  the  impellers 
can  be  in  contact  only  at  one  point  at  the  same  instant — in  no 
position  is  it  possible  for  them  to  touch  each  other  at  two  points 
at  once ;  hence,  there  are  no  shoulders  to  knock  together  when 
the  speed  is  more  than  nominal. 

On  account,  also,  of  there  being  no  popping  due  to  the  ex- 
pansion of  air  when  released  from  the  pockets  in  which  it  has 
been  caught  and  compressed,  and  no  pounding  of  the  impellers 
together,  that  disagreeable  din  and  vibration  usually  associated 
with  machines  of  this  class  is  eliminated,  and  our  blowers  run 
with  practically  no  noise.  This  is  a  feature  that  will  commend 
itself  to  parties  having  had  experience  with  other  pressure 
blowers. 

Another  point  contributing  to  the  evenness  and  uniformity  of 
the  discharge  is  the  fact  that  the  extremities  of  the  impellers 
are  curved.  Thus,  as  they  sweep  past  the  outlet,  there  is  a 
gradual  equalization  of  the  pressure  instead  of  a  sudden  shock, 
such  as  results  from  the  passage  of  two  sharp  edges,  which 
shocks  are  so  detrimental  to  all  working  parts,  as  has  been  noted. 

From  what  has  been  stated,  we  scarcely  need  to  add  that  the 
machine  is  positive  in  its  action.  All  the  air  that  enters  the 
blower  is  inclosed  by  the  impellers,  forced  forward  and  dis- 
charged through  the  outlet  pipe.  The  leakage  is  insignificant, 
and  there  is  no  compressed  air  allowed  to  escape  backward. 
Hence,  all  the  power  applied  to  the  machine  is  used  for  the 
purpose  intended — the  maintenance  of  an  even  blast,  and  none 
of  it  is  wasted  on  needless  work. 

Furthermore,  as  the  contact  between  the  impellers  and  the 


BLOWERS. 


325 


surrounding  case  is  perfect  at  all  times,  the  amount  of  pressure 
that  can  be  developed  and  sustained  depends  solely  on  the 
strength  of  the  machine  and  the  power  applied. 

Each  of  the  two  impellers  is  cast  in  one  piece  and  well  ribbed 
on  the  inside  to  prevent  changes  in  form  under  varying  condi- 
tions. It  is  part  of  our  shop  practice  to  press  the  shaft  into  the 
impeller  with  a  hydrostatic  press,  finish  the  journals  to  standard 
size,  mount  the  impeller  on  a  planer  and  plane  its  entire  surface 
accurately.  By  this  means  we  secure  perfect  symmetry  and  ex- 
actness with  respect  to  the  journal  on  which  it  revolves,  and,  as 
a  consequence,  can  produce  a  machine  that  will  run  more 

FIG.  73. 


HORIZONTAL  BLOWER. 


smoothly,  and  in  either  direction,  at  a  higher  speed  and  press- 
ure than  it  has  been  possible  to  attain  heretofore. 

It  will  be  observed  that  the  cycloidal  curves  produce  an  im- 
peller with  a  broad  waist.  We  have  availed  ourselves  of  this 
to  use  a  high-grade  steel  shaft  of  about  twice  the  sectional  area 
of  those  found  in  competing  machines.  The  advantages  of  this 
need  not  be  enumerated. 

In  Fig.  73  we  illustrate  the  styles  of  blowers  that  are  most 
largely  sold,  i.  e.,  those  pulley  driven.  It  will  be  noticed  that 
we  use  one  pulley  only.  We  can,  however,  when  desired,  put 
a  pulley  on  each  end,  but  because  of  the  large  shafts,  wide-faced 
gears,  and  the  fact  that  there  is  a  bearing  the  entire  distance  from 
the  gears  to  the  impellers,  it  is  seldom  necessary.  In  any  event, 
we  do  not  recommend  two  belts  very  highly,  as,  owing  to  the 


326 


THE    CUPOLA    FURNACE. 


difference  in  the  amount  of  stretch  in  the  leather,  it  is  usually 
the  case  that  one  transmits  most  of  the  power.  Indeed,  it 
sometimes  occurs  that  they  work  against  each  other. 

NUMBERS,  CAPACITIES,  ETC.,  OF   THE   CYCLOIDAL   BLOWERS. 


V* 

1Z 

2 

•? 

, 
1 

r. 

6 

7 

8 

/4 

72 

Capacity  in  cubic  feet  per  rev- 

$6 

1  1/ 

zV* 

8 

I2V« 

2d^ 

d.2 

67 

100 

Ordinary  speed  

/3 
4OO 

•78 

"2  CO 

•7QO 

J/4: 

27C 

2CO 

*r78 

2OO 

-"t/2 
j  7C 

I  ^O 

I2C 

IOO 

Diameter  of  pipe  opening.  .  .  . 

4 

3j6 

8 

*/j 
1O 

o** 

12 

14 

1  /D 

16 

20 

24 

30 

By  "ordinary  speed"  we  mean  what  would  be  about  an 
average  of  every-day  duty.  It  must  be  understood,  however, 
that  the  peculiar  form  of  the  impellers  of  our  blowers,  in  con- 

FIG.  74. 


VERTICAL  BLOWER  AND  ENGINE  ON  SAME  BED-PLATE. 

nection  with  the  other  superior  points  in  construction,  to  which 
we  have  called  attention,  permits  of  higher  speeds  than  com- 
peting machines. 


BLOWERS. 


327 


The  speed  at  which  positive  pressure  blowers  are  run  may  be 
classed  as  "slow;"  therefore,  power  can  be  taken  direct  from 
the  main  line  of  shafting  or  from  a  countershaft  driven  at  the 
same  rate. 

Fig.  74  shows  a  blower  with  an  engine  to  furnish  the  required 
power,  both  on  the  same  bed-plate.  By  such  a  combination  all 
shafting,  pulleys,  gears  and  belts  are  dispensed  with,  as  the 
crank  shaft  of  the  engine  is  coupled  direct  to  a  shaft  of  the 
blower,  thereby  effecting  a  very  simple  but  most  efficient  driving 
arrangement.  We  recommend  the  installation  of  such  a  plant 
when  the  blower  is  to  be  located  at  a  considerable  distance  from 
the  line  shaft,  as  it  will  be  found  more  economical  to  pipe  steam 
to  the  engine  than  to  transmit  power  by  shafting  or  cable.  But 

FIG.  75. 


BLOWER  AND  ELECTRIC  MOTOR. 

even  where  power  is  convenient  there  are  many  good  reasons 
why  it  will  be  found  much  more  desirable  to  operate  the  blower 
with  its  own  engine.  For  instance,  it  can  be  run  independent 
of  the  other  machinery,  as  necessity  or  convenience  may  often 
require,  and  also  permits  the  speed  of  the  blower  to  be  varied, 
as  there  is  a  demand  for  an  increased  or  diminished  amount  of 
blast,  while  otherwise  this  could  not  be  accomplished  without  a 
change  of  pulleys. 


328  THE   CUPOLA   FURNACE. 

In  nearly  every  town  there  is  now  a  station  for  electric-light- 
ing purposes,  and  managers  of  it  are  finding  that  they  can 
extend  the  earning  capacity  of  their  plants  and  increase  their 
profits  by  renting  power  at  a  time  when  otherwise  their  ma- 
chinery would  be  practically  idle.  We  have  arranged  to  have 
our  machines  operated  by  electric  motors  when  desired.  In 
Fig.  75  will  be  found  an  illustration  of  a  motor  geared  direct 
to  a  blower,  both  on  the  same  bed  plate.  When  preferred, 
however,  the  motor  can  be  located  a  short  distance  away,  and 
the  power  transmitted  to  the  blower  pulley  by  means  of  a  belt. 
Foundries  and  other  industries  needing  power  only  to  run  their 
blowers  will  find  it  exceedingly  advantageous  and  economical  to 
adopt  this  plan.  Not  only  will  there  be  a  saving  in  first  cost, 
but  the  operating  expense  will  be  much  less. 

Furthermore,  the  motors  can  have  sufficient  power  to  run  the 
rattler  and  other  light  machines  about  the  establishment. 

GARDEN    CITY    POSITIVE    BLAST    BLOWERS. 

In  Fig.  76  is  shown  the  Garden  City  Positive  Blast  Blower 
manufactured  by  the  Garden  City  Fan  Co.,  Chicago,  111.,  many 
of  which  are  in  use  in  foundries,  and  for  which  claims  are  made 
as  follows : 

The  operation  of  our  blower  is  not  on  the  fan  principle,  in 
which  pressure  is  obtained  by  a  high  velocity  or  speed,  but 
when  the  air  enters  the  case  at  the  inlet  and  is  closed  in  by  the 
vanes  of  the  blower,  it  is  absolutely  confined  and  must  be  forced 
forward  until  finally  released  at  the  outlet,  where  it  must  have 
escape  or  the  blower  stop  if  outlet  is  closed.  There  is  posi- 
tively no  chance  for  loss  by  backward  escapement  of  air,  after 
it  once  enters  the  inlet. 

In  many  respects  our  blower  has  points  of  superiority  over 
any  positive  blower  made,  and  we  call  your  attention  to  the  fol- 
lowing points : 

1st.  It  has  no  gears  whatever.  No  internal  parts  that  require 
attention,  adjustment  or  lubrication. 

2d.  It  fs  only  two  journal  bearings  that  are  external  to  the 
blower  casing.  They  are  self-oiling.  Easy  of  adjustment. 


BLOWERS. 


329 


3d.  Has  no  irregular  internal  surfaces  that  require  contact 
to  produce  pressure,  and  add  friction. 

4th.  Operating  parts  are  always  in  perfect  balance,  thus 
blower  may  be  safely  run  at%a  higher  speed  than  any  positive 
blower  made,  giving  a  proportionate  increase  in  efficiency  and 
a  smaller  blower  may  be  used. 

5th.  A  higher  pressure  can  be  be  obtained  than  is  possible 
with  any  other. 

FIG.  76. 


GARDEN  CITY  POSITIVE  BLAST  BLOWER. 

6th.  The  blowers  are  practically  noiseless  as  compared  with 
all  other  makes. 

ROOTS'S  ROTARY  POSITIVE  PRESSURE  BLOWER. 

The  Roots  Blower  was  designed  by  Mr.  Roots,  of  Connersville, 
Ind.,  nearly  forty  years  ago.  It  is  said  that  it  was  originally 
designed  for  a  turbine  water  wheel,  but  when  the  water  was 
let  in  it  was  all  blown  out,  and  Mr.  Roots  at  once  decided  it 
would  make  a  better  blower  than  a  water  wheel,  and  after  con- 
siderable experimenting,  perfected  it  as  a  blower.  Whether 


330 


THE   CUPOLA   FURNACE. 


this  story  be  true  or  not  we  cannot  say,  but  the  machine  cer- 
tainly makes  a  good  blower,  and  hundreds  of  them  have  been 
used  to  furnish  blast  for  foundry  cupolas.  A  number  of  marked 
improvements  have  from  time  to  time  been  made  in  it  since  it 
was  originally  invented,  and  the  impellers,  which  were  originally 
made  of  wood  placed  upon  iron  shafts  and  covered  with  bee's 
wax  or  soap  to  make  them  air-tight,  are  now  made  entirely  of 
iron  and  accurately  fitted.  The  shape  of  the  blower  cases  has 
also  been  to  some  extent  changed,  and  they  are  now  constructed 
vertical  and  horizontal,  as  shown  in  Figs.  77  and  78.  They  are 

FIG.  77. 


ROOTS'S  VERTICAL  PRESSURE  BLOWER. 

also  made  with  blower  and  engine  on  same  bed-plate  or  with 
blower  and  electric  power  motors  on  same  bed-plate.  The  fol- 
lowing claims  are  made  for  it  by  the  manufacturers,  P.  H.  &  F. 
M.  Roots  Co.,  Connersville,  Ind. : 

1.  It  is  simpler  than  any  other  blower. 

2.  It  is  the  only  positive  rotary  blower  made  with  impellers 
constructed  on  correct  principles. 

3.  It  is  the  best,  because  it  has  stood  the  test  of  years  and  is 
the  result  of  long  experience. 

4.  In  case  of  wear  of  the  journals,  the  impellers  will  not  come 
together  and  break,  or  consume  unnecessary  power,  as  is  the 
case  with  competing  machines. 


BLOWERS. 


33 


5.  The  principles  upon  which  our  blowers  are  constructed 
admit  of  more  perfect  mechanical  proportions  than  any  other. 

6.  The  only  perfectly  adjustable  journal  box  for  this  type  of 
machine  is  used. 

7.  The  gears  are  wide-faced  and  run  constantly  in  oil. 

8.  The  gears  and  journals  are  thoroughly  protected  from  dust 
and  accident. 

9.  Our  machine  blows  and  exhausts  equally  well  and  at  the 
same  time,  and  the  motion  may  be  reversed  at  any  tin%. 

10.  All  the  operating  parts  are  accurately  balanced. 

FIG.  78. 


ROOTS'S  HORIZONTAL  PRESSURE  BLOWER. 

The  principles  upon  which  our  blower  is  constructed  are  so 
radically  different  from  any  competing  machine  that  we  are  en- 
abled to  adopt  proportions  that  are  mechanically  perfect,  and 
hence  we  can  speed  our  machines  much  faster  than  any  other, 
with  a  far  greater  degree  of  safety.  We  are  not  compelled  to 
cut  down  the  weight  of  our  blower  cases,  as  other  manufacturers 
do,  in  order  to  bring  the  weight  of  the  complete  machine  within 
reasonable  bounds.  The  distribution  of  metal  in  the  shafting, 
impellers,  gears  and  cases  of  all  our  blowers  is  perfectly  propor- 
tioned, and  it  is  the  only  rotary  positive  blower  made  so  con- 
structed. 


CHAPTER  XXII. 

CUPOLAS  AND  CUPOLA  PRACTICE  UP  TO  DATE.* 

THERE  are  three  kinds  of  furnaces  employed  in  the  melting 
of  iron  for  foundry  work.  They  are  known  as  the  pot  furnace, 
reverberatory  furnace  and  the  cupola  furnace.  These  fur- 
naces differ  from  each  other  in  construction  and  principle  of 
melting,  and  in  the  days  of  poor  fuel  the  employment  of  the 
pot  furnace  or  reverberatory  furnace  in  the  melting  of  iron  for 
special  work  was  necessary  to  the  production  of  good  castings. 
But,  with  the  discovery  of  veins  of  coal  more  suitable  for  melt- 
ing and  coking  and  the  advancement  made  in  the  manufacture 
of  coke,  the  amount  of  deterioration  to  iron  by  impurities  in 
the  fuel  has  been  reduced  to  a  minimum,  and  the  furnace  that 
will  melt  with  the  smallest  per  cent,  of  fuel  has,  as  a  foundry 
furnace,  been  almost  universally  adopted,  and  the  fuel  that  melts 
iron  most  rapidly  has  almost  entirely  taken  the  place  of  those 
melting  more  slowly.  Charcoal,  the  furnace  fuel  of  years  ago, 
is  only  used  in  foundries  located  in  isolated  districts  where 
other  fuel  is  not  obtainable.  The  use  of  hard  coal  in  melting 
is  almost  entirely  restricted  to  the  anthracite  coal  field,  and 
coke  has  become  the  almost  universal  fuel  for  foundry  work. 

In  the  pot  furnace,  one  ton  of  coke  is  consumed  in  melting  a 
ton  of  iron.  (2240  Ibs.)  In  the  reverberatory  furnace,  from  ten 
to  twenty  cwt.  of  coke  is  required  to  melt  a  ton  of  iron.  In 
the  cupola  furnace,  a  ton  of  iron  may  be  melted  with  one  hun- 
dred and  seventy-two  (172)  pounds  of  coke.  It  will  thus  be 
seen  that  the  cupola  melts  iron  with  a  smaller  per  cent,  of  fuel 
than  either  of  the  other  furnaces.  To  melt  iron  in  a  cupola 

*  Prepared  for  the  first  meeting  of  the  American  Association  of  Foundrymen,  May 
13,  1896,  at  Philadelphia,  Pa. 

(332) 


CUPOLAS   AND   CUPOLA    PRACTICE   UP  TO    DATE.  333 

with  the  small  amount  of  fuel  stated,  the  cupola  must  be  prop- 
erly constructed  and  managed,  which  is  not  always  the  case, 
and  the  consumption  of  fuel  as  a  rule  is  much  greater,  but  is 
still  not  so  large  as  that  required  in  either  of  the  other  furnaces. 
To  reduce  the  amount  of  fuel  required  to  the  smallest  possible 
figure,  a  cupola  must  be  of  a  size  that  will  admit  of  it  being  run 
to  its  fullest  capacity  in  melting  a  heat.  The  tuyeres  must  be 
placed  low  to  prevent  wastage  of  fuel  in  the  bed,  and  the  charg- 
ing aperture  must  be  placed  high  to  utilize  all  the  heat  of  the 
fuel  in  heating  the  stock  and  preparing  it  for  melting  before  it 
enters  the  melting  zone. 

The  rule  for  charging  a  cupola  is  to  place  three  pounds  of 
iron  upon  the  bed  to  each  pound  of  fuel  placed  there,  and  ten 
pounds  of  iron  upon  the  charges  of  fuel  to  each  pound  of  fuel 
in  the  charge.  This  rule  is  not  always  accurately  followed,  but 
it  is  approximately  so,  and  when  the  cupola  is  so  large  that  the 
entire  heat  is  melted  upon  the  bed  in  one  charge  (according  to 
this  rule),  only  three  pounds  of  iron  are  melted  to  the  pound  of 
fuel.  When  ten  charges  are  melted  in  the  same  cupola,  with 
the  same  bed,  eight  pounds  of  iron  are  melted  to  one  of  fuel ; 
and  the  greater  the  number  of  charges,  the  less  the  per  cent,  of 
fuel  required  in  melting,  and  it  is  only  by  melting  a  large 
number  of  charges  and  keeping  the  cupola  in  blast  for  many 
hours,  that  the  small  per  cent,  of  fuel  stated  as  sufficient  to  melt 
a  ton  of  iron,  can  be  made  to  do  the  work. 

Foundrymen,  as  a  rule,  cannot  have  their  cupolas  in  blast 
all  day,  and  are  compelled  to  use  large  cupolas  to  melt  in  a 
given  time  the  amount  of  iron  required  for  their  work,  while 
others  prefer  to  melt  their  iron  rapidly ;  and  it  is  a  question  for 
each  foundryman  to  decide  for  himself,  whether  it  is  more 
economical  to  use  a  large  cupola  and  save  time,  or  a  small  one 
and  save  fuel.  The  height  or  distance  tuyeres  should  be  placed 
above  the  sand  bottom  is  from  two  to  six  inches,  but  they  are 
sometimes  placed  as  high  as  six  feet.  The  general  height  for 
heavy  work  is  from  eighteen  inches  to  thirty-six  inches.  The 
placing  of  tuyeres  at  so  great  a  height  is  productive  of  the 


334  THE    CUPOLA    FURNACE. 

wastage  of  a  large  amount  of  fuel,  for  the  function  of  the  fuel 
placed  below  the  tuyeres  is  to  support  the  stock  in  the  cupola, 
and  it  takes  no  other  part  in  melting  and  is  not  consumed  in 
melting  the  longest  heats.  Its  temperature,  when  a  cupola  is 
in  blast,  is  below  that  of  the  melting  zone,  and  molten  iron  in 
its  descent  through  the  fuel  to  the  bottom  of  the  cupola  is  not 
superheated,  but  its  temperature  is  reduced  to  such  an  extent 
that  hot  iron  can  only  be  tapped  from  a  cupola  with  high 
tuyeres,  when  the  melting  is  so  rapid  that  the  molten  iron  passes 
down  through  the  fuel  under  the  tuyeres  in  such  a  large  volume 
and  so  rapidly,  that  it  is  not  chilled  in  its  descent. 

While  the  fuel  placed  under  the  tuyeres  is  not  consumed  in 
melting,  it  is  heated  to  so  high  a  degree  and  ground  up  to  such 
an  extent  in  the  dump  that  it  is  rendered  worthless  as  cupola 
fuel,  and  every  pound  of  unnecessary  fuel  placed  in  a  cupola, 
by  using  high  tuyeres,  is  a  wastage  of  it. 

It  is  claimed  by  many  foundrymen  that  it  is  necessary  to  have 
tuyeres  placed  high  to  collect  and  keep  iron  hot  for  a  large 
casting.  This  is  one  of  the  fallacies  handed  down  to  us  by  our 
foundry  forefathers,  for  iron  can  be  drawn  from  a  cupola  with 
low  tuyeres  so  much  hotter,  that  it  can  be  kept  hotter  in  a  ladle 
for  any  given  length  of  time  when  properly  taken  care  of  than 
it  can  be  kept  in  a  cupola  with  high  tuyeres.  In  all  cases, 
tuyeres  should  only  be  placed  at  a  sufficient  height  above  the 
sand  bottom  to  admit  of  molten  irons  being  mixed  for  hand-ladle 
work,  and  to  give  sufficient  time  between  taps  for  the  removiag 
and  replacing  of  large  ladles  for  heavy  work. 

Low  charging  doors  are  another  legacy  from  our  ancestors, 
and  in  their  day  the  volume  of  heat  escaping  from  low  cupolas 
was  so  great  that  many  attempts  were  made  to  utilze  this  waste 
for  heating  the  blast,  and  supplying  cupolas  with  a  hot  blast. 
Other  attempts  were  made  to  divert  the  heat  into  side  flues  or 
chambers,  for  heating  the  iron  prior  to  charging;  but  this 
feature  of  the  old  cupolas  has  given  way  more  rapidly  to  modern 
ideas  than  the  high  tuyere,  and  cupolas  in  which  charging  doors 
were  formerly  placed  six  to  eight  feet  above  the  bottom,  now 


CUPOLAS  AND  CUPOLA  PRACTICE  UP  TO  DATE.     335 

have  them  placed  ten  to  fifteen  feet  and  even  higher;  and  all 
the  heat  that  escaped  from  the  low  cupola  is  now  utilized  in 
heating  stock  in  the  cupola  prior  to  melting. 

The  highest  cupolas  in  use  in  this  country  at  the  present 
time  are  those  of  the  Carnegie  Steel  Works,  Homestead,  Pa. 
The  charging  apertures  in  these  cupolas  are  placed  thirty  feet 
above  the  iron  bottom,  and  the  heat  to  so  great  an  extent,  is 
utilized  in  heating  stock  prior  to  melting,  that  it  has  not  been 
found  necessary  to  line  the  iron  stacks,  as  not  sufficient  heat 
to  heat  them  escapes  from  the  cupolas  even  when  the  stock  is 
low. 

A  cupola  to  do  economical  melting  must  not  only  be  prop- 
erly constructed,  but  properly  managed.  In  every  cupola  there 
is  a  inciting  zone  or  belt  in  which  iron  is  melted.  Below  or 
above  this  zone  iron  cannot  be  melted,  but  it  may  be  on  the 
lower  and  upper  edge  of  the  zone,  and  in  either  case  a  dull  iron 
is  the  result.  The  exact  location  of  the  melting  zone  is  deter- 
mined by  the  volume  of  blast.  A  large  volume  places  the  zone 
a  few  inches  higher  and  a  small  one  brings  it  a  few  inches  lower. 
For  this  reason,  cupolas  of  exactly  the  same  construction  fre- 
quently have  higher  or  lower  melting  zones  and  require  a 
greater  or  less  amount  of  fuel  for  a  bed.  The  size  and  arrange- 
ment of  tuyeres  often  increase  or  diminish  the  depth  of  the 
melting  zone,  and  to  obtain  the  best  results  in  melting  the 
location  and  depth  of  the  melting  zone  must  be  learned,  and 
the  weight  of  the  bed  and  charges  varied  to  suit  the  zone. 

The  top  of  the  melting  zone  may  readily  be  determined  by 
the  length  of  time  required  to  melt  iron  after  the  blast  is  put 
on.  If  iron  comes  down  in  five  or  ten  minutes,  the  iron  on  the 
bed  has  been  placed  within  the  melting  zone.  If  it  does  not 
come  down  for  twenty  or  thirty  minutes  after  the  blast  is  on, 
the  iron  has  been  placed  above  the  melting  zone  by  too  great 
a  quantity  of  fuel  in  the  bed,  and  the  delay  in  melting  is  due  to 
the  time  required  in  removing  the  surplus  fuel  by  burning  it 
away.  If  iron  comes  down  in  five  or  ten  minutes  and  is  dull, 
and  at  least  three  pounds  of  iron  cannot  be  melted  to  one  of  fuel 


336  THE   CUPOLA   FURNACE. 

in  the  bed  before  iron  comes  dull,  the  bed  is  too  low  and  the 
iron,  when  melting  began,  was  not  placed  at  the  top  of  the 
melting  zone.  By  noticing  the  melting  in  this  way,  the  height 
of  the  zone  can  readily  be  found  and  the  exact  amount  of  fuel 
required  for  a  bed  determined.  The  depth  of  the  zone  can  be 
found  by  increasing  the  weight  of  the  first  charge  of  iron  until 
the  latter  part  of  the  charge  comes  dull,  which  indicates  that 
it  is  being  melted  too  low  in  the  zone,  and  the  weight  of  the 
charge  should  be  decreased. 

The  quantity  of  fuel  required  for  a  bed  and  the  amount  of 
iron  that  can  be  melted  upon  it  having  been  determined,  tests 
are  then  made  to  ascertain  the  amount  of  fuel  required  in  the 
charges  and  the  amount  of  iron  that  can  be  melted  upon  each 
charge.  The  amount  of  fuel  required  in  each  charge  'is  the 
amount  that  will  restore  the  bed  to  the  same  height  above  the 
tuyeres  at  which  it  was  before  melting  the  first  charge.  This 
is  found  by  increasing  or  decreasing  the  fuel  until  the  melting 
becomes  continuous  and  there  is  no  variation  in  the  tempera- 
ture of  the  iron  at  the  end  of  each  charge.  A  stoppage  or 
slacking  in  the  melting  denotes  that  the  charge  of  fuel  is  too 
heavy  and  the  iron  upon  it  is  placed  above  the  melting  zone. 
Dull  iron  at  the  latter  end  of  a  charge  indicates  that  the  charge 
of  iron  is  too  heavy,  and  so  on  throughout  the  heat. 

By  carefully  noticing  the  melting  in  every  part  of  the  heat, 
the  peculiarities  of  any  cupola  in  melting  may  readily  be  learned, 
and  a  large  amount  of  fuel  saved. 

These  rules  for  melting  are  not  always  followed,  and  in  nine 
cupolas  out  of  ten  too  great  an  amount  of  fuel  is  consumed.  It 
is  a  common  practice  of  melters,  if  not  closely  watched,  to 
gradually  increase  the  fuel  in  charging,  and  when  iron  comes 
dull  they  attribute  it  to  poor  fuel  or  not  enough  of  it,  and  in 
either  case  more  fuel  is  the  remedy,  and  as  a  rule  dull  iron  and 
slow  melting  are  the  result.  Fast  melting  cannot  be  done,  or 
hot  iron  melted,  with  too  large  a  quantity  of  fuel  in  a  cupola. 
The  reason  for  this  is,  that  with  an  excess  of  fuel,  the  iron  is 
placed  above  the  melting  zone  and  the  extra  fuel  must  be  con- 


CUPOLAS  AND  CUPOLA  PRACTICE  UP  TO  DATE.     337 

sumed  before  the  iron  can  come  within  the  zone,  and  the  result 
is  slow  and  irregular  melting. 

Iron  held  just  above  the  zone  for  any  length  of  time  is  heated 
to  so  great  an  extent  that  when  it  enters  the  melting  zone  it 
melts  rapidly  in  one  mass,  and  its  descent  through  the  melting 
zone  in  a  molten  state  is  so  rapid  that  it  is  not  superheated  in 
passing  through  the  zone,  and  drops  through  to  the  bottom  of 
the  cupola  a  dull  iron.  Slow  melting  is  always  the  result  of  an 
excess  of  fuel,  and  dull  iron  is  more  often  the  result  of  an  ex- 
cess than  of  a  deficiency  of  fuel. 

The  per  cent,  of  fuel  required  in  melting  when  a  cupola  is 
properly  constructed  and  managed  depends  entirely  upon  the 
length  of  time  required  to  melt  a  heat.  In  short  heats  of  two 
to  three  hours  eight  pounds  of  iron  to  one  of  coke  may  be 
melted,  and  by  careful  management  good  hot  iron  for  light  work 
be  made.  The  melting  generally  done  in  heats  of  this  length 
is  between  six  and  seven  to  one.  In  long  heats  thirteen  to 
one  has  been  melted,  but  this  ratio  is  seldom  for  any  great 
length  of  time  maintained ;  for  the  quality  of  fuel  varies,  and 
foundrymen  prefer  to  use  a  little  extra  fuel  rather  than  take 
chances  of  a  bad  heat,  and  in  heats  requiring  from  one  to  six 
days  to  melt  the  average  melting  is  about  ten  to  one. 

It  should  be  the  aim  of  every  foundryman  to  reduce  his  melt- 
ing to  a  system.  He  should  first  see  that  the  cupola  is  properly 
constructed,  and  then  study  its  working  in  the  manner  described. 
When  this  has  been  learned,  a  slate  should  be  made  out  and 
-given  to  the  melter,  indicating  the  exact  amount  of  fuel  to  be 
placed  in  the  bed  and  charges,  and  the  exact  amount  of  iron  in 
each  charge,  as  well  as  the  amount  of  each  brand  of  iron  or 
scrap  in  it. 

As  the  lining  burns  out  and  the  cupola  diameter  increases,  the 
weight  of  charges  of  fuel  and  iron  should  be  increased  to  cor- 
respond with  the  enlargement  of  the  cupola.  An  accurate 
cupola  record  should  be  kept  and  the  amount  of  fuel  consumed 
in  melting  compared  with  each  carload  or  lot  of  coke,  to  prove 
that  no  extra  fuel  is  being  used  by  the  melter.  When  such  an 

22 


338  THE   CUPOLA   FURNACE. 

account  is  accurately  kept  by  every  foundryman,  much  less  fuel 
will  actually  be  consumed  in  melting  than  at  the  present  day, 
and  at  the  same  time  claims  of  melting  ten  to  one  in  short  heats 
and  fifteen  or  twenty  to  one  in  long  heats  will  no  longer  be 
heard. 


CHAPTER  XXIII. 

CUPOLA   SCRAPS. 
BRIEF    PARAGRAPHS    ILLUSTRATING  IMPORTANT   PRINCIPLES. 

Make  a  heat,  take  a  heat,  make  a  cast,  make  a  mould,  run  a 
melt,  casting,  moulding,  are  all  terms  used  in  different  sections 
of  the  country  to  indicate  the  melting  of  iron  in  a  cupola  for 
foundry  work. 

When  iron  runs  dull  from  a  cupola,  draw  all  the  melted  iron 
off  at  once  and  prevent  the  newly  melted  iron  being  chilled  by 
dropping  into  dull  iron  in  the  bottom  of  the  cupola. 

When  slag  flows  from  a  tap-hole  with  a  stream  of  iron,  when 
the  iron  is  not  drawn  off  too  close,  it  is  due  to  too  much  pitch 
in  the  sand  bottom. 

The  formation  of  slag  in  a  spout  is  due  to  poor  material  used 
in  making  up  the  spout. 

Some  foundrymen  do  not  seem  to  know  what  hot  iron  is,  for 
they  call  all  kinds  of  B.  S.  hot  iron,  if  it  will  run  out  of  the  ladle. 

The  cutting  out  of  the  spout  lining  in  holes  by  the  stream  of 
molten  iron  is  due  to  a  deficiency  of  cohesive  properties  in  the 
lining  material  when  heated  to  a  high  temperature. 

When  a  tap-hole  closes  up  with  slag  and  cannot  be  kept 
open,  the  slag  is  generally  produced  by  the  melting  of  the  ma- 
terial used  in  making  up  the  front  and  tap-hole.  Slag  made  in 
the  cupola  flows  from  the  tap-hole  without  clogging  it. 

A  little  sand  or  clay-wash  added  to  the  front  and  spout 
material  will  generally  correct  the  deficiencies  in  the  material 
and  save  the  melter  a  great  deal  of  trouble  with  his  spout  and 
tap-hole. 

In  a  spout  with  a  broad  flat  bottom  the  stream  takes  a  differ- 
ent course  at  every  tap,  the  spout  soon  becomes  clogged  with 

(339) 


340  THE   CUPOLA   FURNACE. 

cinder  and  iron,  the  molten  iron  flows  in  all  directions,  and  the 
spout  looks  like  a  small  frog  pond  with  patches  of  scum.  Make 
the  bottom  of  the  spout  narrow  and  concentrate  the  stream  in 
the  center. 

If  the  sand  bottom  does  not  drop  readily  when  the  doors  are 
dropped,  there  is  too  much  clay  in  the  bottom  material.  Mix 
a  little  sand  and  cinder  riddled  from  the  dump  with  it,  or  some 
well-burnt  moulding  sand. 

A  hard  rammed  bottom  causes  iron  to  boil  in  a  cupola  the 
same  as  in  a  hard  rammed  mould,  and  is  frequently  the  cause  of 
a  bottom  cutting  through.  A  bottom  should  be  rammed  no 
harder  than  a  mould. 

Wet  sand  in  a  bottom  not  only  causes  iron  to  boil,  but 
hardens  it.  Bottom  sand  should  be  no  wetter  than  moulding 
sand  when  tempered  for  moulding. 

Exclusively  new  sand  should  not  be  employed  in  making  a 
bottom.  The  old  bottom  with  a  few  shovels  of  sand  riddled 
from  the  gangways  makes  the  best  bottom  material. 

Often,  a  melter  " don't  know"  why  the  cupola  is  working 
badly,  because,  if  he  knew,  he  would  be  discharged  at  once  for 
carelessness. 

A  bad  light-up  makes  a  bad  heat.  The  bed  must  be  burned 
evenly  or  it  will  not  melt  evenly. 

If  the  wood  is  not  all  burned  up  before  iron  is  charged,  the 
wood  smokes  and  the  melter  can  not  see  where  to  place  the  fuel 
and  iron  when  charging.  Never  use  green  wood  for  lighting  up. 
When  green  wood  is  used  for  lighting  up,  the  bed  is  frequently 
burned  too  much  before  the  wood  is  burned  out,  and  the  cupola 
is  free  of  smoke. 

Don't  burn  up  the  bed  before  charging  the  iron.  When  the 
fuel  is  well  on  fire  at  the  tuyeres  and  the  smoke  is  all  burned 
off,  put  in  the  front,  close  the  tuyeres  and  charge  the  iron  at  once. 

If  anything  happens  to  delay  putting  on  the  blast  after  the 
fire  is  lighted,  do  not  let  that  delay  charging  the  iron,  for  the 
bed  will  last  longer  with  the  iron  on  it  than  it  will  with  it  off. 
Charge  the  iron  as  soon  as  the  bed  is  ready  for  charging  ;  close 


CUPOLA   SCRAPS.  341 

the  front  and  tuyeres  and  open  the  charging  door  to  stop  the 
draught,  and  the  cupola  may  be  left  to  stand  for  hours  and  as 
good  a  heat  be  melted  as  if  no  delay  had  occurred. 

A  melter  who  burns  up  his  tapping  bars  so  that  two  have  to 
be  welded  together  to  make  one  almost  every  heat,  don't  know 
how  to  put  in  a  front  or  make  his  bod  stuff. 

The  amount  of  fuel  wasted  every  year  in  the  United  States 
by  the  use  of  high  tuyeres  in  cupolas  is  sufficient  to  make  a 
man  very  rich. 

A  new  cupola  always  effects  a  great  saving  in  fuel,  but  it  is 
often  hard  to  find  the  fuel  (saved)  at  the  end  of  the  year.  A 
little  more  practical  knowledge  in  managing  the  old  cupola  will 
often  enable  the  foundryman  to  find  the  fuel  saved  and  price  of 
the  new  cupola  besides. 

Never  run  a  fan  in  its  own  wind  merely  to  show  a  high  press- 
ure on  the  air-gauge. 

The  volume  of  blast  supplied  to  a  cupola  should  be  regulated 
by  the  speed  of  the  blower  and  not  by  the  size  of  tuyeres. 

That  old  "  no  blast"  story  of  the  melter  has  had  its  day  among 
-practical  foundrymen. 

The  air-gauges  in  use  at  the  present  time  for  showing  the 
pressure  of  blast  on  a  cupola  are  an  excellent  thing  to  prevent 
a  poor  melter  from  claiming  he  has  no  blast  and  blaming  a  bad 
heat  on  the  engineer,  for  the  gauge  always  shows  a  higher 
pressure  of  blast  when  the  cupola  is  bunged  up  from  poor  man- 
agement. 

High  tuyeres  in  a  cupola  are  an  inheritance  left  us  by  our 
forefathers  in  the  foundry  business,  of  which  we  have  never 
got  rid. 

The  only  general  improvement  made  in  tuyeres  in  the  past 
fifty  years  has  been  in  increasing  them  to  a  size  that  will  admit 
the  blast  freely  to  a  cupola.  The  only  local  improvement  has 
been  in  placing  them  lower. 

Molten  iron  should  be  handled  in  a  ladle  and  not  held  in  a 
cupola.  Nothing  is  gained  by  holding  iron  in  a  cupola  to  keep 
it  hot. 


342  THE   CUPOLA   FURNACE. 

"  I  will  let  that  go  for  to-day,  and  to-morrow  I  will  take  more 
time  and  fix  it  right,"  is  a  remark  frequently  made  by  melters. 
That  kind  of  work  is  often  the  cause  of  a  very  bad  heat. 

Pig-iron  melts  from  the  ends,  and  the  shorter  it  is  broken  the 
quicker  it  will  melt. 

Tin-plate  scrap  may  be  melted  in  a  cupola  the  same  as  cast 
iron.  It  throws  off"  sparks  from  the  tap  hole  and  spout  similar 
to  hard  cast  iron. 

The  fins  on  castings  made  from  tin-plate  scrap  must  be 
knocked  off  with  the  rammer,  for  the  castings  are  too  hard  and 
brittle  to  be  chipped  or  filed. 

The  loss  of  metal  in  melting  tin-plate  scrap  in  a  cupola  is  not 
so  great  as  in  melting  iron  when  melted  with  a  light  blast,  but 
the  loss  may  be  as  great  as  25  per  cent,  when  melted  with  a 
very  strong  blast. 

The  cost  of  melting  iron  in  a  cupola  is  about  two  dollars 
per  ton. 

The  cost  of  melting  tin-plate  scrap  in  a  cupola  is  from  three 
to  four  dollars  per  ton. 

Galvanized  sheet  iron  scrap,  when  melted  with  tin-plate 
scrap,  reduces  the  temperature  of  the  molten  metal  to  such  an 
extent  that  it  cannot  be  run  into  moulds. 

Anthracite  coal  picked  from  the  dump  of  a  cupola  will  not 
burn  alone  in  a  stove  or  core  oven  furnace,  and  it  is  very  doubt- 
ful if  it  produces  any  heat  when  burned  with  other  coal  in  a 
cupola. 

Lead  is  too  heavy  and  penetrating  when  in  a  fluid  state  to 
be  retained  in  a  cupola  after  it  has  melted.  The  ladle  should 
be  warmed  and  the  tap  hole  left  open  when  melting  this  metal 
in  a  cupola. 

The  best  lining  material  for  a  cupola  in  which  tin-plate  scrap 
is  melted  is  a  native  mica  soap-stone. 

The  sparks  that  fly  from  a  stream  of  hard  iron  at  the  tap 
hole  and  spout  are  the  oxide  of  iron.  They  are  short-lived  and 
burn  the  flesh  or  clothing  very  little. 

The  sparks  from  a  wet  tap-hole  or  spout  are  molten  iron,  and 
burn  wherever  they  strike. 


CUPOLA  SCRAPS.  343 

We  have  probably  chipped  out,  daubed  up  and  melted  iron 
in  a  greater  number  of  cupolas  and  in  more  different  styles  of 
cupola  than  any  melter  in  the  United  States,  and  in  heats  that 
require  from  two  or  three  hours  to  melt,  and  we  have  found 
that  8  pounds  of  iron  to  I  pound  of  best  coke  ;  7  pounds  of  iron 
to  i  pound  of  best  anthracite  coal ;  6  pounds  of  iron  to  I  pound 
of  hard  wood  charcoal ;  4  pounds  of  iron  to  I  pound  of  gas-house 
coke,  is  very  good  melting.  We  have  done  better  than  this  in 
test  heats,  but  do  not  consider  it  practicable  to  melt  iron  for 
general  foundry  work  with  less  fuel  than  stated  above. 

The  best  practical  results  for  melting  for  general  foundry 
work  are  obtained  from  6^  to  7  pounds  of  iron  to  I  pound  of 
coke;  5  to  6  pounds  of  iron  to  I  pound  of  hard  coal;  4  to  5 
pounds  of  iron  to  I  pound  of  hard  wood  charcoal ;  3  Ibs.  of 
iron  to  I  pound  of  gas-house  coke. 

A  less  per  cent,  of  fuel  is  required  in  long  heats  than  in  short 
ones,  for,  as  a  rule,  three  to  one  is  charged  on  the  bed  and  ten 
to  one  on  the  charges,  and  the  greater  the  number  of  charges 
melted,  the  less  the  per  cent,  of  fuel  consumed. 

Ten  pounds  of  iron  to  one  of  coke  are  melted  at  the  Home- 
stead Steel  Works,  in  cupolas  that  are  kept  in  blast  night  and 
day  for  six  days. 

Less  fuel  is  generally  required  to  melt  iron  in  the  foundry 
office  than  is  required  to  melt  it  in  a  cupola. 

Use  a  light  blast  when  melting  with  charcoal  or  gas-house 
coke. 

If  you  go  into  the  foundry  whe#  the  heat  is  being  melted  and 
find  the  tap-hole  almost  closed,  the  spout  all  bunged  up  and 
the  melter  picking  at  the  spout  with  a  tap  bar  and  running  a 
rod  into  the  tap-hole  a  yard  or  so  in  his  efforts  to  get  the  iron 
out,  and  remark  to  him :  "  You  are  having  some  trouble  with 
your  cupola  to-day,"  he  will  say :  "  Yes,  we  have  some  very 
bad  coke  to-day,  sir;  that  last  car  is  poor  truck;"  or,  "We  are 
melting  some  dirty  pig  or  scrap  to-day,  sir."  He  never  thinks  : 
"We  have  a  very  poor  melter  to-day,  sir." 

At  the  first  meeting  of  the  American  Association  of  Foundry- 


344  THE   CUPOLA    FURNACE. 

men,  held  in  Philadelphia,  May  12,  13,  14,  1896,  one  of  the 
delegates  was  Mr.  C.  A.  Treat,  a  good-sized  practical  foundry- 
man  weighing  over  300  pounds,  and  representing  the  C.  A. 
Treat  Mfg.  Co.,  Hannibal,  Mo.  After  the  meeting  had  effected 
a  permanent  organization,  transacted  all  its  business  and  was 
about  to  adjourn,  Mr.  Treat  arose  and  in  his  quiet  way  re- 
marked :  "  Gentlemen  :  Since  we  have  have  formed  an  organ- 
ization of  foundrymen  for  our  mutual  benefit,  don't  you  think 
it  would  be  a  good  idea  for  foundrymen  to  stop  lying  to  each 
other?"  The  burst  of  laughter  that  followed  this  remark  was 
loud  and  long.  It  would  be  a  great  relief  to  many  foundrymen 
if  some  foundrymen  would  take  the  hint  and  stop  lying  about 
the  large  amount  of  iron  melted  with  a  small  amount  of  fuel, 
fast  melting,  etc. 

A  few  years  ago,  a  foundryman  who  was  about  to  publish  a 
work  on  foundry  practice,  being  desirous  to  obtain  some  reli- 
able data  on  cupola  practice,  had  several  hundred  blanks  printed 
and  sent  to  foundrymen  in  different  parts  of  the  country,  with 
the  request  that  they  fill  in  the  amount  of  fuel  placed  in  the  bed 
and  charges,  the  amount  of  iron  placed  on  bed  and  charges, 
diameter  of  cupola,  height  of  tuyeres,  etc.  He  was  surprised 
at  the  reports  received  in  reply.  Many  of  them  showed  that 
the  men  who  filled  in  the  blanks  either  knew  nothing  at  all 
about  a  cupola,  or,  knowing  the  report  was  to  be  published, 
were  desirous  of  making  an  excellent  showing  of  cupola  work  in 
their  foundries,  and  in  many  of  the  reports  the  cupola  was  filled 
with  stock  in  such  a  way  that  not  a  pound  of  iron  could  have 
been  melted  in  a  cupola  charged  as  indicated  in  the  formula. 
In  some  cases,  the  amount  of  fuel  placed  in  the  bed  was  not 
sufficient  to  fill  to  the  tuyeres  a  cupola  of  the  diameter  given ; 
in  others,  the  fuel  placed  in  the  charges  was  not  sufficient  to 
cover  the  iron  and  separate  the  charges ;  and  it  was  only  after 
pointing  out  these  mistakes  and  returning  the  reports  for  cor- 
rection, in  some  cases  two  or  three  times,  that  they  were  put  in 
any  kind  of  shape  for  publication. 

Some  fifteen  years  ago,  when  we  took  a  more  active  part  in 


CUPOLA  SCRAPS.  345 

melting  than  at  the  present  time,  and  occasionally  published  an 
account  of  heats  melted,  we  were  repeatedly  criticised  in  print 
by  some  would-be  melters,  who  were  melting  anywhere  from 
ten  to  twenty  to  one,  for  using  too  large  a  quantity  of  fuel,  and 
some  times  were  invited  to  come  to  their  foundries  and  get  a 
few  points  on  melting  before  publishing  another  work  on  the 
subject.  We  have  never  learned  of  any  of  our  critics  on  the 
fuel  question  becoming  prominent  in  foundry  matters  or  rich  in 
the  foundry  business,  and  presume  they  have  all  saved  their 
employers  such  a  large  amount  of  fuel  in  melting  that  they  have 
been  placed  upon  the  retired  list  with  half  pay. 

The  heats  published  at  that  time  were  the  best  that  could 
be  melted  in  the  cupolas  described,  and  the  amount  of  fuel  con- 
sumed was  generally  about  seven  to  one  with  hard  coal  and 
eight  to  one  with  best  Connellsville  coke.  The  foundrymen 
who  at  the  present  time  melt  heats  of  the  same  size  in  cupolas 
of  the  same  diameter,  with  a  less  per  cent,  of  fuel,  are  like  an- 
gels' visits,  few  and  far  between. 


NOTE. 


PAXSON-COLLIAU   CUPOLA. 

On  page  193  are  shown  illustrations  of  the  Paxson-Colliau  Cupola  as  built  by 
J.  W.  Paxson  Co.,  Philadelphia,  and  on  page  194  we  have  stated  that  this  is  a  hot  blast 
type  similar  to  that  made  by  Victor  Colliau. 

We  desire  to  correct  the  above  to  the  extent  that  the  Paxson-Colliau  Cupola  is  not 
claimed  to  be  of  the  Hot  Blast  type,  and  while  it  has  two  zones  of  melting  as  has  the 
Colliau,  there  have  been  made  many  changes  in  its  construction,  bringing  it  up  to  date. 

The  new  Paxson-Colliau  has  a  low  safety  tuyere  which  discharges  any  overflow  into 
a  cornucopia-shaped  trap  fitted  with  a  soft  metal  plug,  which  is  easily  melted,  and 
should  any  hot  iron  or  slag  strike  it,  it  is  discharged  outside  through  the  bottom 
plate,  as  shown  by  Fig.  44,  page  193. 

This  cupola  is  also  fitted  with  a  fine  Screen  Charging  Door,  as  shown  by  Fig.  43, 
same  page,  requiring  no  lining,  and  is  claimed  to  be  more  acceptable  than  the  old 
solid  cast  iron  doors,  as  it  does  not  warp  or  crack.  It  may  be  fitted  with  a  new 
arrangement  to  hold  up  the  bottom  doors,  instead  of  the  old  prop,  when  a  small  car 


346  THE   CUPOLA   FURNACE. 

or  truck  on  wheels  or  rake  can  be  placed  under  the  cupola  to  receive  the  hot  drop 
and  carry  it  into  the  foundry  if  desired,  which  is  often  done  during  cold  weather  to 
keep  the  shop  warm,  or  to  keep  it  out  of  the  way,  perhaps  in  the  yard,  where  it  can 
be  cooled  off  by  water,  and  gotten  ready  for  the  cinder  mills.  The  cupola  then  will 
cool  off  quickly,  allowing  any  repairs  to  be  made  or  patching  up  the  burned-out  por- 
tions. 

A  new  device  of  a  Spark  Arrester  is  also  placed  over  the  Paxson-Colliau  Cupola, 
which  confines  the  sparks  and  dirt  to  a  small  area.  The  lower  tuyeres  are  rectangular 
and  flared,  and  the  upper  ones  are  oval;  they  are  staggered  so  that  there  is  very  little 
dead  plate;  the  blast  reaches  every  part  where  it  is  wanted,  being  distributed  evenly. 
Therefore  the  lining  is  not  affected  by  the  action  of  the  blast  to  the  extent  that  would 
be  expected  where  upper  and  lower  tuyeres  are  used  and  two  zones  of  melting  are  at 
work. 

While  speaking  of  this  it  may  be  mentioned  that  we  have  seen  the  naked  hand 
placed  in  the  Paxson-Colliau  furnace  at  the  charging  door  during  the  greater  part  of 
the  heat  without  injury.  Did  you  ever  try  this  in  an  ordinary  cupola  while  running 
a  heat?  The  hand  will  be  pulled  back  very  quickly.  This  proves  the  fact  that  there 
is  enough  oxygen  admitted  through  the  small  upper  tuyeres  to  make  a  more  perfect 
combustion  of  the  fuel  where  it  is  wanted,  both  below  and  above  the  tuyeres. 

A  new  mercury  blast  gauge  is  supplied  with  each  cupola.  It  is  made  of  iron  and 
japanned,  except  the  brass  scale-plate  and  glass  tube.  This  is  the  neatest  looking  and 
most  common-sense  gauge  we  have  yet  seen.  A  further  description  of  this  cupola 
may  be  had  from  the  builders,  J.  W.  Paxson  Co.,  Philadelphia,  Pa.  E.  K. 


INDEX. 


A  BENDROTH  BROS., Port  Chester, 
J\  N.  Y.,  cupola  re- 

port of,  214,215 
Port  Chester,  N.Y., 
cupola  with  three 
rows   of  tuyeres 
used  by,  43 
Port  Chester,  N.Y., 
large  cupola    in 
the    foundry   of, 
198-202,298 
Accounts,  cupola,  214-221 

manner  of  keeping,  214 
Adjustable  tuyeres,  45,  46 
Air,  admission  of,  to  the  cupola,  30 
-chamber,  14-16 

admission  of  blast  to,  15, 

16 

area  of,  5,  6 

belt,  connecting  blast  pipes 
with  tuyeres  direct  from 
a,  286-290 

construction  of,  14,  15 
location  of,  14 
openings  in  the,  16 
perfect  manner  of  connect- 
ing the  main  pipe  with 
an,  290 

round  or  over-head,  objec- 
tion to,  15 

chambers,  air  capacity  of,  15 
best,  15 

perfect  connection  of,  286 
cubic  feet  of,  required  to  melt  a 

ton  of  iron,  293,  294 
friction  of,  in  pipes,  281,  282 
gauges,  292,  341 
means  of  supplying,  to  a  cupola, 

294 
required  for  the  combustion   of 

fuel,  295,  296 
restriction     to    the    passage    of, 

through  the  cupola,  294 
rule  for  estimating  the  amount  of 
power  required   to   displace  a 
given   amount  of,   at   a   given 
pressure,  318 


American  Blower  Co.,  Detroit,  Mich., 

Smith's  Dixie  fan  blower  built  by 

the,  309-311 
Angle  iron  or  brackets  for  the  support 

of  the  lining  of  a  cupola,  23,  24 
Anthracite  coal,  amount  of,  required 

to  melt  iron,  90 

BAD  melting,  cause  of,  247 
caused  by  wood  and  coal, 

250,  251 

examples  of,  233-253 
Banking  a  cupola,  277-279 
Bar  for  cutting  away  the  bod,  93 
Bars,  tapping,  92,  93 
Baskets  for  measuring  fuel,  230 

increase  in  size  of,  212 
Bed,  the,  77-79 

best  depth  of,  125 

burned  too  much,  poor  melting 

due  to,  249,  250 
burning  the,  340 

up  the,  for  warming  the  cu- 
pola, 77 

depth  of  fuel  in  the,  78 
effect  of  too  large  a  quantity  of 

fuel  in  a,  128 
fuel  required  for  a,  79 
leveling  the  top  of  the,  82 
quantity  of  fuel  for  a,  336 
raising  or  lowering  a,  78,  79 
uneven  burning  of  the,  253 

up  of  the,  effect  of,  77 
Belt  air   chamber,   connecting  blast 
pipe  with  tuyeres  direct  from  a,  286- 
290 

Bessemer  steel  works,  location  of  tuy- 
eres in  cupolas  used  in,  53 
Blakeney  cupola,  204,  205 

tuyere,  35,  36 
Blast,  85,  86 

admission  of,  to  the  air-chamber, 

15,  16 
air-chamber    for    supplying    the 

tuyeres  with,  14 
arrangement  for  supplying,  266 
cause  of  apparent  deficiency  of,  91 


(347) 


348 


INDEX. 


Blast,  direct  delivery  of,   to  tuyeres, 

284 

furnace,  definition  of  a,  136 
fuel  required  in,  1 
use  of  lime-stone  in  the,  135, 

136 

gate,  advantage  of  the,  290,  291 
gates,  290-292 
gauges,  292-294 
heating  the,  274 
in  melting,  294-299 
indications  of,  when  first  put  on, 

85 
length  of  time  the,  can  be  taken 

off  a  cupola,  276,  277 
machines  for  supplying,  294 
passage  of,  through  heated  fuel, 

127 

pipe,    preventing    gas   from   the 
cupola  from  passing  into  the,  85 
pipes,  279-281 

blast  gates,  276-299 
connection  of,  with  cupolas, 

284 

diameter  of,  281-290 
explosion   in,    blast   gauges, 

blast  in  melting,  276,  277 
explosions  in,  292 
galvanized  iron,  280,  281 
long,  poor  melting  caused  by, 

materials  for,  280 

poor  arrangement  of,  286-288 

table   of  diameter  and   area 

of,  285 

table  showing  the  necessary 
increase  in  diameter  for  the 
different  lengths  of,  283 
underground,  279,  280 
very  best  way  of  connecting, 

with  tuyeres,  288-290 
positive     and     non-positive, 

294,  295 

putting  on  the,  85 
taking  off  the,  during  a  heat, 

276-299 

time  for   charging   the   iron 
before  putting  on  the,  86,  87 
Blower  and  electric  motor,  327 
Buffalo  steel  pressure,  301-309 
connection  of  tuyeres  with,  5 
Cpnnersville  cycloidal,  321-328 
directions    for    setting    up,    314, 

316,317 

efficiency  of,  317,  318 
foundation  for,  300 
Garden   City  positive  blast,  328, 
329 


Blower,  Green  patented  positive  pres- 
sure, 314-321 
horizontal,  325 
Mackenzie,  311-314 
obtaining  the  best  results  from  a, 

303 

on  adjustable  bed, and  on  bed  com- 
bined  with 
c  o  untershaft, 
303-305 

combined  with 
double  up- 
right engine, 
305,  306 

placed  near  cupola,  290 
placing,  300,  301 
prevention  of  the  destruction  of 

a,  300,  301 
Roots  "s  rotary  positive  pressure, 

329-331 

Smith's  Dixie  fan,  309-311 
vertical,  and  engine  on  same  bed, 

326 
Blowers,  300-331 

cycloidal,    numbers,    capacities, 

etc.,  of,  326 

forced  blast  pressure,  311-331 
foundry,  speed  of,  320,  321 
standard  foundry,  driven  by  pul- 
ley, table  of  dimensions  of,  in 
inches,  319 
table  of  speed  and  capacities  of, 

as  applied  to  cupolas,  309 
Blue  clays  for  spout  lining,  68 
Bod  bar  for  cutting  away  the,  93 
definition  of,  94 
good,  qualities  of  a,  95 
for  small  cupolas,  95 
horse  manure  as  an  essential  of 

a  good,  95 
material,  94,  95 

working  the,  96 
mixture  for,  95 
mode  of  making  the,  96 
size  and  shape  of,  96 
sticks,  93,  94 
wet,  explosion  of  iron  caused  by 

a,  257 

Boiling,  cleaning  iron  by,  147,  148 
Bolton  Steel  and  Iron  Co.,  England, 

use  of  Ireland's  cupola  in,  159 
Bosh,  taper  from  the,  to  the  lining,  109 
Boshing  of  cupola,  14 
Bottom  door,  4 

bolts  and  latches  of,  4 
Bottom  doors.  11,  12 

devices    for    raising    the, 
133,134 


INDEX. 


349 


Bottom  doors,  way  for  reducing  size 

and  weight  of,  25 

Bottom,  exclusively  new  sand  in  a,  340 
hard  rammed,  340 
high  pitch  of,  66 
hollow,  66 

of  cupola,  height  of,  3,  11 
pitch  or  slope  of,  65,  66 
plate,  4 

plates,  shape  of,  26 
sand,    introduction   of,   into   the 

cupola,  63,  64 
preparation  of,  63 
renewal  of,  64 
re-use  of,  63 

too  wet  or  too  hard,  conse- 
quence of,  65 
tuyere,  46-49 
uneven  settling  and  breaking  of, 

10 

wet  sand  in  a,  340 
Brackets,  arrangement  of,  23-26 
Brick,  curved,  for  lining,  22 
for  casing,  111 
split,  112 

Bridging,  cause  of,  99,  100 
Buffalo  blower  for  cupola  furnaces  in 

iron  foundries,  308,  309 
electric  blower  built  in  "  B  "  and 

steel  pressure  types,  306-308 
Forge  Co.,  Buffalo,  N.  Y.,  bank- 
ing a  cupola  at 
the,  277-279 
table  of  diameter 
of    blast    pipes 
prepared   by 
the,  281-283 
School    Furniture    Co.,    Buffalo, 

N.  Y.,  cupola  of  the,  54 
steel  pressure  blower,  301-309 
Byram    &   Co.  Iron  Works,  Detroit, 
Mich.,  cupola  report  of,  214-216 


,  melting  of,  224 
'\s  Carbon,  effect  of,  upon  cast  iron, 

145 

removal  of,  from  iron,  145 
Carnegie   Steel   Works,    Homestead, 

Pa.,  cupolas  in  the,  275,  298,  335 
Cars  for  removing  the  dump,  100 
Casing,  12-14 

brick  for  the,  111 

cupola,  construction  of,  12 

lining  of,  6,  7 

preventing  the,  from  rusting  off 

at  the  bottom,  25 
refractory  material  for  lining,  21 , 
22 


Casing,  stack,  2,  5 

construction  of,  12 
strain  upon  the,  12 
thickness  of,  12 

lining,  to  protect  the, 

111 

wrought  iron,  5 
Casings,  4,  5 
Cast,  make  a,  339 

iron,   quantity  of,    that  can    be 

melted  in  a  cupola,  224 
size  and  weight  of  a  piece  of, 
that  can  be  melted  in  a  cu- 
pola, 224 
Casting,  339 
Castings,  fins  on,  342 

report  of,  219 

Center  blast  cupola,  Ireland's,  159-161 
tuyeres,  experiments  with, 

298,  299 

Chain  blast,  294 
Charcoal,    experiments   in   softening 

iron  with,  130-132 
use  of,  as  fuel,  332 
Charge,  fuel  required  in  each,  336 
Charges,  division  of  fuel  andiron  into, 

212 
effect  of  too  large  a  quantity  of 

fuel  in  the,  128 
for  experimental  heats,  126,  127 

most  even  melting,  127 
placing  the,  82-84 
table  of,  200 
Charging,  80-82 

bad,  poor  melting  due  to,  84 
cupola  slate  for,  and  cupola   re- 
port, 220 

cupolas,  different  ways  of,  113 
door,  6,  14 

distance  of  the  floor  of  the 

scaffold  below  the,  26 
location  of,  13 
wear  of  lining  at  the,  110 
doors,  low,  334,  335 
flux,  84,  85 
proper  way  of,  84 
rule  for,  333 
time  for,  132,  133 
Chenney  tuyere,  41 
Chill  mould,  explosion  of  iron  in  a, 

259 
Chipping  out,  101-103 

tools  for,  255 

Cincinnati,  O.,  poor  melting  in  a  cu- 
pola at,  251-253 
Cinder,  brittle,  making  a,  136 
chipping  off,  106 
tendency  of,  in  a  cupola,  136, 137 


350 


INDEX. 


Clam  shells,  142 

Clay,  amount  of  sand  in,  for  daubing, 

104 

and  sharp  sand,  mixtures  of,  62 
effect  of  too  much,  in  lining,  68 
blue,  for  daubing,  104 
fire,  for  daubing,  104 

soaking  of,  104 
sands,  62 
wash,  63 

yellow,  for  daubing,  104 
Clays  for  spout  lining,  68 
Coal  and  wood,  bad  melting  caused 

by,  250,  251 
anthracite,   amount  of,  required 

to  melt  iron,  90 
hard,  use  of,  as  fuel,  332 
melting  with,  130 
Cogniardelle,  294 

Coke,  Connellsville,  amount  of,   re- 
quired to  melt  iron,  90 
consumption  of,  in  melting  iron, 

332 
picking  out  of,  from  the  dump, 

101 

use  of,  as  fuel,  232 

Colliau  cupola,  claims  for  the,  194-196 
history  and  description  of, 

193,  194 

patent  hot-blast  cupola,  192-196 
-Paxson  cupola,  193.  194 

cupola,  note  on  the,  345,  346 
tuyere,  41 

Combination  stick,  93,  94 
Combustion,  complete,  178 
Connersvillecycloidal  blower,  321-328 
Contact,  point  of,  definition  of,  323 
Continuous  slot  tuyere,  34,  35 
Copper,  melting  of,  223 
Corry,  Pa.,  Pevie  cupola  at,  186 
Cost  of  melting,  230-232 
Crandall  improved  cupola  with  John- 
son patent  center  blast  tuyere,  202- 
204 
Crates,  iron,  for  removing  the  dump, 

100, 101 
Crucible,  experiments  in  a,  with  iron, 

130 

Cupola  account,  correctness  of,  221 
accounts,  214-221 

manner  of  keeping,  214 
admission  of  air  to  the,  30 
and  stack,  weight  of,  9 
banking  a,  277-279 
best  supports  for  a,  10 
Blakeney,  204,  205 
blower  placed  near,  290 
book,  231 


Cupola,  boshed,  burning  out  of  the 

lining  of  the,  109 
new  lining  in,  105, 106 
boshing  of,  14 
bottom,  height  of,  11 
brackets   or  angle   iron   for  the 

support  of  the  lining  of  a,  23, 24 
brick  walls  for  the  support  of  a,  10 
bridged  sectional  view  of  a,  107, 

108 

burning  of  iron  in  a,  88 
casing,  construction  of,  12 
cause   of  bridging  and  hanging 

up  refuse  in  a,  99,  100 
charging  a,  80-82 
chipping  out  the,  101-103 
Colliau  patent  hot  blast,  192-196 
combined  tuyere  area  of  a,  49,  50 
commencement  of  melting  in  a. 

86 

construction  of  a,  8-29 
Crandall  improved,  with  Johnson. 

patent  center  blast  tuyere,  202- 

determination  of  the  location  of 

the  melting  zone  in  a,  123 
does  it  pay  to  slag  a?  141,  142 
dumping  the  refuse  from  the,  9& 
economical  melting  in  a,  335 
effect  of  limestone  in  a,  138 
expanding,  155-157 
experiment  to  learn  at  what  point 

of  the,  iron  melts,  114 
experimental,  114 
for  melting  tin-plate  scrap,  227, 

228, 229 
for    tin-plate   scrap,   best   lining 

material  for  a,  342 
foundation,  2,  9,  10 
furnace,  1-7,  332 

advantages  of,  1 
chief  use  of,  223 
consumption  of  coke  inr 

332 

description  of,  2 
fuel  required  in,  1 
supply  of  air  to  the,  30 
Greiner  patent  economical,  188- 

192 

hardening  of  iron  in  a,  88 
height  of  a,  13 

the  bottom  of,  3 
Herberts,  173-182 

for  melting  steel,  182-184 
highest,  in  use,  335 
holding  molten  iron  in  the,  88 
house,  novel  plan  of  construction, 
of  a,  27,28 


INDEX. 


351 


Cupola,  how  to  slag  a,  140,  141 

introduction  of  the  bottom  sand 

into  the,  63,  64 
Ireland's,  157-159 

center  blast,  159-161 
iron  support  for  a,  10 
Jumbo,  198-202,  298 
large,  lighting  up  a,  76 
learning  to  manage  a,  209,  210 
length  of  time  the  blast  can  be 

taken  off  a,  276,  277 
lining,  life  of,  110 

renewal  of,  12 

locating  the  tap  hole  in  the,  73 
location  of,  8 

of  slag  hole  in  a,  74,  75 
Mackenzie,  170-173 
management,  58-112 
means  of  supplying  air  to  a,  294 
melting  capacity  of,  14,  30 

iron  in  a,  terms  used  to  in- 
dicate, 339 

tin-plate  scrap  in  a,  225-229 
zone  or  melting  point  of  a, 

77 

modern,  casing  or  shell  of,  12 
necessity  of  learning  the  peculiar- 
ities in  the  working 
of  every,  58 
understanding  the,  to 
do  good  melting,  207 
newly  lined,  trouble  in  melting  in 

a,  79 
number  of  hours  a,  will  melt  iron 

freely,  224 

old,  theory  of  melting  in  the,  296 
style,  construction  of,  149-152 
English,  154,  155 
spark  catcher  in,  263,  264 
picks,  102,  103 
pit  of,  3,  4 

Paxson-Colliau,  193,  194 
Pevie,  184-186 
placing  charges  in  the,  82-84 

tuyeres  in  a,  20,  21 
point  of  melting  in  a,  113 
practical  instructions  for  charg- 
ing and  managing  a,  129 
working  of  a,  81 
preparation  of  a,  for  a  heat,  208 
putting  in   two   fronts   and    tap 

holes  in  a,  73,  74 
record,  accurate,  337 
requirements  of  the  foundryman 

from  the,  91 
requisites  for  melting  iron  in  a, 

332,  333 
report,  Abendroth  Bros.,  214,215 


Cupola  report,  Byram  &  Co's,  214, 216 

reports,  misleading,  90 
unreliability  of,  344 

reservoir,  152,  153 

restriction  to  the  passage  of  air 
through  the,  294 

rule  for  charging  a,  333 

scrap,  charging  of,  83 

scraps,  339-345 

sectional  view  of  a,  at  Cincinnati, 
251,252 

size  and  weight  of  a  piece  of  cast 
iron  that  can  be  melted  in  a,  224 

slate  for  charging,  and  cupola  re- 
port, 220 

small,  lighting  up  a,  76 

space  of  melting  iron  in  a,  77 

spout,  old  way  of  making,  67 

stationary  bottom,  154, 155 

Stewart's,  186-188 

stopping  in  a,  88 

straight,   adhesion    of    slag    and 
cinder  to  the  lining  of,  106 

supports  of,  2,  3 

tank  or  reservoir,  167-170 

tendency  of  slag  and  cinder  in  a, 
136, 1^7 

tuyeres,  30-57 

two-hour,  170 

Voisin's,  161-163 

warming  up  a,  248-250 

waste  heat  from  a,  274, 275 

weight  of  slag  drawn  from  a,  137, 
138 

what  a,  will  melt,  223,  224 

Whiting,  196-198 

with  tuyeres  near  the  top,  129 

Woodward's  steam  jet,  163-167 
Cupolas,  amount  of  fuel  required  for 
the  bed  of,  79 

and  cupola  practice  up  to  date, 
332-338 

casings  of,  2 

connection  of  blast  pipes  with,  284 

different  styles  of,  149-205 
ways  of  charging,  113 

fluxing  of  iron  in,  135-148 

for  heavy  work,  location  of  tuy- 
eres in,  53 

height  and  size  of  door  for,  13, 14 
of  tuyeres  in,  above  sand 
bottom,  19,  20 

hot  blast,  271-275 

in  machine  and  jobbing  found- 
ries, location  of  tuyeres  in,  53 

large,  tap-holes  for,  16,  17 

location  of  a  greater  number  of 
tuyeres  in,  54 


352 


INDEX. 


Cupolas,  melting  of  lead  in,  223-224 
mistake  of  placing  small  tuyeres 

in,  49 
modern,    spark   catching    device 

for,  264-266 

number  of  tuyeres  in,  2 
odd-shaped,   shaping  the  lining 

of,  109 
of    large    diameter,    location    of 

tuyeres  in,  52 
of  very  small  diameter,  location 

of  tuyeres  in,  52,  53 
old  style,  149-152 
patent,  shaping  the  lining  of,  109 
props  for,  60,  61 
shapes  of,  2 
size  of,  333 
sizes  of,  2 
small,  bod  for,  95 

breaking  away  the  bridge 

in,  99 

dumping  of  99 
support  of  the  stock  in,  60 
tap  hole  for,  1 6 
smaller,  location   of   tuyeres  in, 

52 
spark  catching  devices  for,  263- 

270 
table  of  speed  and  capacities  of 

blowers  as  applied  to,  309 
use  of  limestone  in,  136 
with  high  tuyeres,  impossibility 
of  making  hot  iron  for  light 
work  in,  52 

with  two  tap  holes,  slope  of  bot- 
tom in,  67 

Cylinder  blower,  294 
Cycloidal  blowers,  numbers,  capaci- 
ties, etc.,  of,  326 
curves,  322 

DAUBING,  103-105 
application  of,  105 
object   of  application  of,  to  a 

lining,  105 
poor,  cheap,  nothing  gained  by 

using,  104,  105 
substances  used  for,  103 
thickness  of,  on  a  lining,  107 
wet,  explosion  of  iron  by,  262 
Detroit,    Mich.,    novel  plan   of  con- 
struction of  a  scaffold  and   cupola 
house  at,  27,  28 
Diamond  Drill  and  M'f'g  Co.,  Birds- 

boro,  Pa.,  cupola  of  the,  46 
Doherty  tuyere,  33,  34 
Door,  charging,  6, 14 

location  of,  13 


Door,  for  cupolas,  height  and  size  of, 

13, 14 
Doors,  bottom,  11,12 

devices  for  raising  the,  133, 
134 

devices  for  raising  the,  in  place, 
59.  60 

dropping  the,  61,  62 

heavy,  best  device  for  raising,  134 

putting  up  the,  59-61 

sliding,  4 

small,  device  for  raising,  134 

supports  of,  60 
Double  tuyere,  42,  43 
Drying  the  lining,  58,  59 
Dump,  breaking  up  the,  101 

chilling  the,  99 

constitution  of  the,  100 

handling  of  the,  100 

picking  over  the,  101 

removing  the,  11,  100,  101 
Dumping,  98-100 

CLEVATOR,  9 

C     Elizabethport,  N.  J.,  tests  with 
the   Herbertz  cupola  at,  176, 
179-182 
England,   Ireland's  cupola   patented 

in,  157 

use  of  tanks  in,  169 
English  cupola,  old  style,  154,  155 
Expanded  tuyere,  32,  33 
Expanding  cupola,  155-157 
Experiments  in  melting,  113-134 
Explosion  of  molten  iron,  257-262 
Explosions  in  blast  pipes,  292 

blast  gauges, 
blast  in 
melting, 
276,  277 

FAN  blower,  Smith's  Dixie,  309-311 
Fire  clay  for  daubing,  104 

soaking  of,  104 
Fire-proof  scaffold,  26-29 
Floor,   explosion    of  iron   by  falling 

upon  the,  258 
Fluor  spar,  146,  147 
Flux,  charging  of,  84,  85 
definition  of,  135 
effect  of,  upon  iron,  138 
fluor  spar  as  a,  146,  147 
quantity  of,  required,  84 
Fluxes,  action  of,  on  lining,  139 
materials  used  as,  135 
mineral,  effect  of,  on  a  front  ma- 
terial, 72 
use  of,  135 


INDEX. 


353 


Fluxing,  improper,  injury  to  iron  by, 

143, 144 

of  iron  in  cupolas,  135-148 
tin-plate  scrap,  228 
Foundation,  block  in  the,  to  rest  the 

prop  upon,  60 
construction  of,  10 
cupola,  2,  9,  10 
Foundries,    disturbances   in   melting 

in,  205 

number  of  men  employed  in,  230 
Foundry  blowers,  speed  of,  320,  321 
standard,  driven  by  pul- 
ley,   table    of   dimen- 
sions of,  in  inches,  319 
department,       Lebanon       Stove 

Works,  daily  report  of,  217 
Outfitting    Co.,    Detroit,    Mich.,  ; 
cupola  manufactured  by,  202-  j 
204 
result    of   keeping    an   accurate 

melting  account  in  a,  231 
work,  furnaces  employed  for,  332 
general,  best  practical  results 

for  melting  for,  343 
Foundry  man,    requirements    of   the, 

from  the  cupola,  91 
Foundrymen,  theory  of  melting  not 

understood  by,  212 
Forced  blast  pressure  blowers,  311- 

331 
Front,  71-73 

drying  of  the,  7  2 

material,  effect  of  mineral  fluxes 

on,  72 

for  putting  in  the,  71 
poor,  effect  of,  72 
top  wet,  effect  of,  72 
putting  in  the,  71 
thickness  of,  72 
Fuel,  90-92 

air  required  for  the   combustion 

of,  295,  296 

amount  of,  in  each  charge,  81 
required  for  a  bed,  79 

in  each  charge,  336  j 
and      iron,     division      of,      into 

charges,  212 

arranging  the,  for  lighting  up,  76 
consumption    of    too    great    an  ! 

amount  of,  336 
under  the  tuyeres, 

50,51 

depth  of,  in  the  bed,  78 
distribution  of  the  charge  of,  83 
effect  of  too  large  a  quantity  of,  j 

in  a  bed,  128 
much,  230,  231 

23 


Fuel,  guessing  the  weight  of,  212 

heated,  passage  of  blast  through. 

127 

heating  of,  in  a  cupola,  129 
measuring  of,  230 
old  way  of  placing  the,   in  the 

cupola,  80 
proportion  of,  to  iron  for  melting, 

90 

quantity  of,  for  a  bed,  336 
required  in  various  furnaces,  1 
too  heavy  charges  of,  effect  of,  81 
too  light  charges  of,  effect  of,  81 
under  the  tuyeres,  121,  122,  334 
value    of,   wasted  every  year  in 

the  United  States,  53 
waste  of,  341 
weight  of  the  charges  of  iron  to 

the  charges  of,  82 
Furnace,  blast,  definition  of  a,  136 

use  of  limestone  in  the, 

135,  136 

cupola,  1-7,  332 
kinds  of,  332 
pot,  332 

reverberatory,  332 
Furnaces,  various,  fuel  required  in,  1 

p  ALVANIZED  sheet  iron  scrap,  342 
VJT  melting 

of,  227 
Garden  City  positive   blast  blowers, 

328, 329 
Gas,  preventing  the  passage  of,  into 

the  blast  pipe,  85 
Gases,  escaping,  composition  of,  177, 

178 

free  oxygen  in  the,  178 
Gates,  charging  of,  83 
Gauges,  blast,  292-294 
Glasgow,  Scotland,  use  of  Stewart's 

cupola  at,  186-188 
Gould  &  Bberhardt,  scaffold  in  the 

foundry  of,  at  Newark,  N.  J.,  28 
Green    patented     positive    pressure 

blower,  314-321 
Greiner  patent   economical    cupola, 

188-192 
tuyere,  45 

Grout,  composition  of,  6 
Grouting  for  lining,  22 

HEARTH  in  the  Herbertz  cupola  at 
Elizabethport,  N.  J.,  180 
movable,    of    the    Herbertz 

cupola,  173 

Heat,    escaping,   attempts  to   return 
the,  to  the  cupola,  273,  274 


354 


INDEX. 


Heat,  make  a,  339 
take  a,  339 
taking  off  the  blast  during  a,  276- 

299 

theory  of  the  production  of,  44,  45 
utilization  of,  275 
waste,  from  a  cupola,  274,  275 
plans  for  the  utilization    of, 

271 

utilization  of,  1,  2,  13 
Heats,    experimental,    charges    for, 

126, 127 
Height  of  cupola  bottom,  11 

tuyeres,  50-53 
Herbertz  cupola,  173-182 

for  melting  steel,  182- 

184 
test-heats  with  the,  176, 

177 
Hibler,  B.  H. ,  bottom  tuyere  patented 

by,  48 
Horizontal  and  vertical  slot   tuyere, 

36,37 

blower,  325 
slot  tuyere,  34 
Horse  manure  as  an  essential   of  a 

good  bod,  95 
Hot  blast  cupolas,  271-275 

IMPELLER,  complete,  316 
Iron,  additional,  charging  of.  83 
affinity  of  limestone  for,  136 
amount  of  anthracite  coal  re- 
quired to  melt,  90 
combined  with  the 

slag,  142 

Connellsville    coke 
required  to  melt, 
90 
limestone  required 

for,  137 

placed     upon     the 
bed   in    the   first 
charge,  81 
and     fuel,     division    of,     into 

charges,  212 

arrangement  of,  in  the  experi- 
mental cupola,  114-119 
art  of  melting,  211,212 
burning  of,  in  a  cupola,  88 
carbonized,  use  of,  as  softeners, 

145 

cast,  effect  of  carbon  upon,  145 
quantity   of,    that    can   be 

melted  in  a  cupola,  224 
size  and  weight  of  a  piece 
of,  that  can  be  melted  in 
a  cupola,  224 


Iron,  cause  of  the  variations  in  the 
weight  of  the  first  charge  of, 
82 
change  in  the  action  of  the,  at 

the  spout,  66 
charging,  340,  341 

large  pieces  of,  224 
cleaning   of,    by   boiling,  147, 

148 

consumption  of  coke  in  melt- 
ing, 332 

contents  of,  in  slag,  138 
cost  of  melting,  342 
cubic   feet   of  air  required  to 

melt  a  ton  of,  293,  294 
deception  in  the  quality  of  the, 

at  the  spout,  66 
dull,  cause  of,  336 
effect  of  flux  upon,  138 
silicon  on,  144 
tin  on,  227 
too  heavy  a  charge  of, 

128 
experiments  in  softening  with 

charcoal    130-132 
with,  in  a  crucible, 

130 
explosion  of  molten  iron,  by, 

258,  259 

first  melted,  chilling  and  hard- 
ening of,  87 

fluxing  of,  in  cupolas,  135-148 
furnaces  employed  in  melting 

of,  332 

guessing  the  weight  of,  212 
hard,  experiments  in  softening, 

51 
hard,  softening,  130-132 

sparks  from,  258 
hardening  of,  in  a  cupola,  88 
high  silicon,  Southern,  use  of, 

in  stove  foundries,  144,  145 
hot  and  of  even  temperature, 

melting  of,  208 
for  light  work,  impossibil- 
ity of  making,  in  cupolas 
with  high  tuyeres,  52 
impossibility  of  melting,  under 

the  tuyeres,  51 
improvement   of,  in   a  cupola 

furnace,  143 

indication  of  the  melting  by  the 
flow  of,  from   the  tap  hole, 
88,89 
injury  to,  by  improper  melting 

and  fluxing,  143,  144 
malleable,  experiments  in  mak- 
ing, 143 


INDEX. 


355 


Iron,  melted  high  in  a  cupola,  cause 

of  dullness  of,  128 
melting  of,  correct  theory  of,  80 
in  a  cupola,  no  chance 
work  in,  207 
terms  used  to 
indicate  the, 
339 
things   to  be   learned    in, 

209 
molten,    explosion   of,   64,  65, 

257-262 
filtering  of,  through  slag, 

84,85 

handling  of,  341 
holding  of,  in  the  cupola, 
88 


poling  of,  147,  148 
ber  of 


numer  o    hours  a  cupola  will 

melt,  224 
old  way  of  placing  the,  in  the 

cupola,  80 

over,  mould  for,  222 
picking  out  of,  from  the  dump, 

101 
placing  the  first  charge  of,  on 

the  bed,  80 
in  the  cupola,  83 
point  of  melting,  in  a  cupola, 

113 
proportion  of  fuel  to,  for  melt- 

ing, 90 
recovery  of,    from   the   dump, 

101 

removal  of  carbon  from,  1-15 
requisites  for  melting,  in  a  cu- 

pola, 332,  333 

space  of  melting,  in  a  cupola,  77 
theory  of  preventing,  from  run- 

ning into  the  tuyeres,  102 
time  for  charging,  132,  133 

the,    before    the 
blast  is  put  on, 
86,87 
too  heavy  charges  of,  effect  of, 

81 

light  charges  of,  effect  of,  81 
tuyeres  to  improve  the  quality 

of,  55,  56 

weight  of  the  charges  of,  to  the 
charges  of  fuel,  82 
first  charge,  81 
Ireland,  Mr.,  bottom  tuyere  used  by,  j 

48 

double  or  two   rows  ofj 
tuyeres  devised  by,  42  j 
Ireland's  center  blast  cupola,  159-161 
cupola,  157-159 


Isbell  Porter  Co.,  Newark,  N.J., blower 
built  by  the, 
312 

Mackenzie  cu- 
pola, manu- 
factured by, 
170-173 

J  AGGER,  Tread  well  &  Perry,  cupo- 
las constructed  by,  271-273 
Jamestown,  N.  Y.,  tuyeres  in  a  cupola, 

31 
Jobbing  foundry  cupolas,  location  of 

tuyeres  in,  53 
Johnson,   Mr.,  experiments  of,  with 

the  center  blast  tuyere,  299 
Johnson,  John  D.,  &  Co.,  Hainesport, 
N.  J.,  action  of  fluxes  on  lining  of 
cupola  of,  139 
Jumbo  cupola,  198-202,  298 

table  of  charges  of,  200 

T/NOEPPEL,    Mr.,    on   banking  a 
IV  cupola,  277-279 

LADLE,  damp,  iron  caused  to  boil 
by  a,  262 

Lawrence  reducing  tuyere,  38,  39 
Lead,  melting  of,  in  cupolas,  223 

molten,  handling  of,  342 
Leather  bellows,  294 
Lebanon  Stove  Works,  daily  report  of 

foundry  department  of,  217 
Light-up,  bad,  340 
Lighting-up,  76,  77 

wood  for,  340 
Limestone,  action  of  a  large  per  cent. 

of,  137 

affinity  of,  for  iron,  136 
amount  required  of,  137 
charging  of,  140 
effect  of,  in  a  cupola,  138 
in  large  quantities,  136-138 
object  of  use  of,  136 
use  of,  in  blast  furnace,  135,  136 

cupolas,  136 
Lining,  21-23 

action  of  fluxes  on,  139 

belly  of,  107 

brackets  or   angle   iron   for  the 

support  of  the,  23,  24 
burning  away  of  the,  at  the  melt- 
ing zone,  110 
out  of,  24,  25 
cupola,  life  of,  110 
destruction  of,  at  and  below  the 

tuyeres,  110 
drying  the,  58,  59 


356 


INDEX. 


Lining,  effect  of  fluor  spar  on  the,  146 
too  much  clay  in,  68 
sand  in,  68 
false,  22,  111,  112 
filling  in  the,  at  the  melting  zone, 

106, 107 

greatest  wear  of,  110 
laying  up  a,  22 
material,  best,  342 

for  spouts,  68 
new,  in  cupola,  105,  106 
object  of  applying  daubing  to  a, 

105 
of  boshed  cupola,  burning  out  of 

a,  109 
old,   false   lining  over  the,  111, 

112 
out  of  shape,  sectional  view  of, 

235,  237,  239,  241 
prevention  of  absorption  of  mois- 
ture by  the,  25,  26 
refractory  material  for,  6,  7 
renewal  of,  12 
selection  of  a,  139 
settling  of,  25 
shaping  the,  105-110 
split  brick,  112 
spout,  67 

stack,  wear  of,  110 
support  of,  5 
taper  of,  107 

to  the,  from  the  bosh,  109 
thickness  of,  22,  110 

daubing  on  a,  107 
to  protect  the  casing, 

111 

wear  of,  at  the  charging  door,  110 
Loading,  old  way  of,  80 
Loam  clays  for  spout  lining,  67 

sands,  62 

Loams  for  bods,  94 
Lobdell  Car  Wheel  Co.,  Wilmington, 
Del.,  melting  cannon  at  the  foundry 
of,  224 
Low  tuyeres,  122, 123 

McGILVERY,  WM.  &  CO.,  acci- 
dent in  the  foundry  of,  259,  260 
Machine  foundry  cupolas,  location  of 

tuyeres  in,  53 

Mackenzie  blower,  311-314 
cupola,  170-173 
tuyere,  34,  35 
Magee  Furnace  Co.,  Boston,  Mass., 

triangular  tuyere  used  by  the,  39 
Malleable  iron,  experiments  in  mak- 
ing, 143 
Marble  spalls,  142, 143 


Marsh,  James,  explosion  of  iron   in 

the  foundry  of,  Ii60 
Massachusetts,  early  use   of  bottom 

tuyere  in,  48 
Melt,  run  a,  339 
Melter,  aim  of  every,  255,  256 
directions  by  the,  210 
good,  interference  with  a,  254, 255 
poor,  254 

practical  and  scientific,  254 
process  of  chipping  out  by  the, 

101-103 

skill  of  the,  seen  at  the  tap  hole,  98 
whims  of,  210 
Melters,  254-256 

no   attention   paid   by  many,  to 

shape  the  cupola,  105 
theory  of  some,  102 
Melting,  86-89 

account,  accurate,  result  of  keep- 
ing a,  231 
art  in,  205-210 
bad,  cause  of,  247 

caused  by  wood  and    coal, 

250,  251 

examples  of,  233-253 
best  practical  results  for,  343 
blast  in,  294-299 

capacity,  increase  in  the,  by  two 
or  three  rows  of  tuyeres,  21 
of  a  cupola,  30 
commencement  of,  86 
cost  of,  230-232 

per  ton,  mode  of  figuring, 

231,232 

disturbances  in,  205 
economical,  335 
experiments  in,  113-134 
fast,  207 

galvanized  sheet-iron  scrap,  227 
good,  necessity  of  understanding 

the  cupola  for,  207 
improper,  injury  to  iron  by,  143, 

144 
indication  of  the,  by  the  flow  of 

iron  from  the  tap  hole,  88,  89 
iron,  art  of,  211.  212 

correct  theory  of,  80 
cost  of,  342 

hot  and  of  an  even  tempera- 
ture, 208 
in  a  cupola,  no  chance  work 

in,  207 

terms  used   to  in- 
dicate the,  339 
things  to  be  learned  in,  209 
most  even,  charges  for,  127 
point,  77 


INDEX. 


357 


Melting  point,  discovery  of  the,  77 
in  a  cupola,  113 
to  find  the,  78 
poor,  caused  by  long  blast  pipes, 

290 
due  to  the  bed  being  burned 

too  much,  249,  250 
in  a  Cincinnati  cupola,  251- 

253 
preparation  of  tin-plate  scrap  for, 

225 

reduction  of,  to  a  system,  214,  337 
scrap  sheet  iron,  227 
sheet  of  Syracuse  Stove  Works, 

218 
slow,  207,  208 

and  irregular,  337 
cause  of,  337 

study  of  the  materials  used  in,  209 
theory  of,  in  the  old  cupola,  296 
not  understood  by  foun- 

drymen,  212 
tin-plate  scrap,  cost  of,  342 

experiments  in,  226, 

227 

in  a  cupola,  225-229 
with  coal,  130 
zone,  77,  123-120 

burning  away  of  the  lining 

at  the,  110 
depth  of,  125 

determination  of  the  location 

of    the, 

123,  335 

top  of, 335, 

336 

development  of  the,  129 
filling  in  the  lining  at  the, 

106, 107 

location  of  the,  77 
raising  aud  lowering  the,  120, 

Mercury  gauges,  292 

Metal  from  tin  plate  scrap,  doctoring 

of,  227 
quality     of, 

225,  226 

gray,  from  tin-plate  scrap,  226 
Moisture,  prevention  of  the  absorp- 
tion of,  by  the  lining,  25,  26 
Molding  sand  for  spout  lining,  67 
Molten  iron,  explosion  of,  257-262 
Mould  for  over  iron,  222 
Moulder,  aim  of  every,  210 
Moulding,  339 

floors,  cleanings  from,  63 
sand,  use  of,  for  daubing,  103 
sands  for  bods,  94 


M.  Steel  Co.,  Springfield, O.,  Blakeney 
cupola  man- 
ufactured by 
the,  204,205 
tuyere  used  in 
the  cupola, 
constructed 
by  the,  35,  36 

Mud,  explosion  of  iron  when  poured 
into,  260 

\TAU,  J.  B.,  on  the  Herbertz  cupola, 
|  IN     173-182 

North  Bros.,  explosion  of  iron  in  the 
foundry  of,  260,  261 

O'KEEFE,  J.,    spark    catcher,    de- 
signed by,  266-268 
;  Oval  tuyere,  32 
Over  iron,  mould  for,  222 
J  Oyster  shells,  142 

Oxygen,  free,  in  the  escaping  gases, 
178 

PARIS,  D.  E.,  &  CO.,  West  Troy, 
I      N.  Y. ,  bad  melting  at  the  foundry 

of,  242-248 
Paxson-Colliau  cupola,  193,  194 

note  on  the,  345, 

346 

Perry  &  Co.,  cause  of  having  to  dump 
a  cupola  at  the  foundry 
of,  253 

examples  of  bad  melting 
at  the  foundry  of,  233- 
242 

Pevie  cupola,  184-186 
Picks,  cupola,  102,  103 
Pig  iron,  placing  the,  in  the  cupola, 

_82,83 

Pipe,  main,  perfect   manner  of  con- 
necting the,  with  an  airchamber,290 
I  Pipes,  blast,  279-281 

branch,  area  of,  284 
friction  of  air  in,  281-282 
I  Piston  blower,  294 
Pit,  cupola,  3,  4 
Pit  lining,  3 
Platform  scales,  21 1 
Point  of  contact,  definition  of,  323 

melting,  discovery  of  the,  77 
Poking  the  tuyeres,  89 
Poling  molten  iron,  147,  148 
Poor  melting  in  a  Cincinnati  cupola, 

251-253 
Pot  furnace,  332 

consumption  of  coke  in,  332 
fuel  required  in,  1 


358 


INDEX. 


Power,  rule  for  estimating  the  amount 
of,  to  displace  a  given  amount  of 
air  at  a  given  pressure,  318 

Pratt  &  Whitney,  charging  large 
pieces  of  iron  at  the  foundry  of,  224 

Props,  60,  61 

removing  the,  61,  62,  99 

Providence  Locomotive  Works,  visit 
to  the  plant  of,  248-250 

RANSOM   &  CO.,  Albany,  N.  Y., 
cupola  at  the  stove  foundry  of,  273 
Records,  blanks  for,  221 

value  of,  214 
Reducing  tuyere,  Lawrence,  38,  39 

Truesdale,  37,  38 

Refractory  material  for  lining,  6,  7 
Relining  and  repairing,  110-112 
Repairing  and  relining,  110-112 
Report,  cupola,  Abendroth  Bros. ',21 4, 

215 

Byram&  Co. 's,  214,21 6 
daily,    of    Foundry    department 

Lebanon  Stove  works,  217 
of  castings,  219 
Reports,  blanks  for,  221 
false,  221 
keeping  of,  221 
Reservoir  cupola,  152,  153 

or  tank  cupola,  167-170 
Return   flue   cupola    spark    catcher, 

266-268 
Reverberatory  furnace,  332 

consumption    o  f 

coke  in,  332 
fuel  required  in,  1 
Reversed  T  tuyere,  37 
Richmond,  Ind.,  sectional  view  of  a 

bridged  cupola  at,  107,  108 
Riddles,  increase  in  size  of,  212 
Roots' s      rotary     positive      pressure 

blower,  329-331 
Round  tuyere,  31,  32 

ST.  LOUIS,  MO.,  large  cupola  with 
two  tuyeres  in,  54 
Sand,  amount  of,  in  clay  for  daubing, 

104 
bottom,  62-67 

destruction  of  the,  64 
elements  to  contend  with 

in  the,  65 
height  of    tuyeres   above, 

19,  20,  333,  334 
leakage  of,  64 
perfect  joint  between  the, 
and  the  spout  lining,  68, 


Sand  bottom,  pitch  or  slope  of,  64 
riddling  out  of  the,  101 
slushing  the,  64 
effect  of  too  much,  in  lining,  68 
for  bottom,  working  of,  65 
for  sand-bottom,  62 
mould,  explosion  of  iron  in  a,  259 
moulding,  use  of,  for  daubing,  103 
sharp,  for  daubing,  104 
Sash  weights,  226 
Scaffold,  7,  8,  9 

construction  of,  9 

distance  of  the  floor  of,  below  the 

charging  door,  26 
exposure  of,  to  fire,  26,  27 
fire  proof,  9 
location  of,  26 
novel  plan  of  construction  of  a, 

27.28 

old  worn-out  scales  upon  the,  213 
scales  in  the  floor  of,  211 
Scaffolds,  best  and  safest,  28,  29 

devices  for  rendering  fire-proof, 

27,28 

Scale,  size  of,  211 
Scales  and  their  use,  211-213 

old  worn-out,  213 
Scrap,  charging  of,  83 

galvanized   sheet    iron,    melting 

of,  227 

heavy  government  melting  of, 224 
rusted,    explosion   of  iron  when 
brought  in  contact  with,  260, 
262 

sheet  iron,  melting  of,  227 
tin-plate,  cupola  for  melting,  227, 

228,  229 
experiments  in  melting, 

226,  227 
fluxing  of,  228 
melting  of,  in  a  cupola, 

225-229 

preparation  of,  for  melt- 
ing, 225 

Shaping  the  lining,  105-110 
Shavings  for  lighting  up,  76 
Sheet  blast  tuyere,  34 

iron  scrap,   galvanized,    melting 

of,  227 

melting  of,  227 
Shells,  142 

crackling  of,  142 
Silicon,  effect  of,  on  iron,  144 
j  Size  of  tuyeres,  49,  50 
I  Skinner  Engine  Co.,  explosion  in  the 

the  cupola  of,  261,262 
Slag,  amount  of  iron  combined  with 
the,  142 


INDEX. 


359 


Slag,  chilling  of,  75 
chipping  off,  106 
closing  up  of  the  tap  hole  with, 

339 

contents  of,  138 
filtering  molten  iron  through,  84, 

85 

formation  of,  in  a  spout,  339 
hole,  74,  75 
front,  75 
location  of  the,  17,  18,  140, 

141 

impurities  in  the,  141 
in  cupola,  breaking  down  the,  102 
position  of,  in  the  cupola,  18 
removal  of,  from  the  spout,  70 
tapping  of,  17,  51,  53 
tendency  of,  in  a  cupola,  136, 137 
time  for  drawing  of,  1 41 
weight  of,  drawn  from  a  cupola, 

137,  138 

Slagging  a  cupola,  140,  141 
cost  of,  141,  142 
saving  effected  by,  141 
trouble  in,  140 
Slate,  cupola,  for  charging,  and  cupola 

report,  220 
Sledging,  bars  for,  92 
Sliding  doors,  4 

Smith's  Dixie  fan  blower,  309-311 
Smithfield,  N.  J.,  Pevie  cupola  at,  186 
Soapstone  for  daubing,  104 
Softening  hard  iron,  130-132 
Spark   catcher,    return   flue    cupola, 

266-268 
catching  device,  best,  269,  270 

for  modern  cupolas, 

264-266 

oldest  and  most  effi- 
cient, 263,  264 
devices  for  cupolas,  263-270 

various,  268,  269 
Sparks,  258,  342 

objections  to,  5 
Speed  of  foundry  blowers,  320-321 

ordinary,  definition  of,  326 
Split-brick,  112 
Spout,  17,  18,  67-70 

building  the  sides  of  the  lining 

of,  69 
change  in  the  action  of  the  iron 

at  the,  66 

choking  up  of  the,  69 
coating  of  the,  70 
damp,  boiling  of  iron  in  a,  257 
deception  in  the  quality  of  the 

iron  at  the,  66 
formation  of  slag  in  a,  339 


Spout,  lining,  67 

cutting  out  of  the,  in  holes, 

339 

drying  of  the,  72 
greatest  strain  upon  the, 69,70 
making  up  of  the,  68 
perfect  joint  between  the,  and 

the  sand  bottom,  68,  69 
old  way  of  making,  67 
removal  of  slag  from  the,  70 
shaping  the  lining  of  the,  70 
size  of,  17 

wet,  explosion  of  iron  in  a,  257 
with  a  broad  flat  bottom,  339,  340 
Spouts,  lining  material  for,  68 
modern,  67 

short,  common  practice  in,  69 
Stack  and  cupola,  weight  of,  9 
casing,  2.  5 

construction  of,  12 
contracted,  5 
contraction  of,  12 
enlarged,  5,  269 
enlarging  of,  12,  13 
height  of,  5 
lining,  renewal  of,  12 
thickness  of,  22,  23 
wear  of,  110 
size  of,  5 

Standard  foundry  blowers  driven  by 
pulley;  dimensions  in  inches,  table 
of,  319 

Stationary  bottom  cupola,  154,  155 
Steam  jet,  advantages  of  the,  175 

cupola,  Woodward's,  163-167 
Steel,  Herbertz   cupola  for  melting, 

182-184 

spring  gauges,  292 
Stewart's  cupola,  186-188 
Stocking,  modern  way  of,  80 

old  way  of,  80 

Stopping-in  and  tapping,  96-98 
devices  to  assist  in,  97,  98 
difficulties  in,  97 
knack  in,  97 
mode  of,  97 
Stove  foundries,  breakage  in,  145 

height  of  tuyeres  in,  20 
sand  for  bottom  used  in, 

62,63 

use  of  high  silicon  South- 
ern iron  in,  144,  145 
Straight  Line  Engine  Co.,  Syracuse, 
N.  Y.,  scaffold  in  the  foundry  of, 
28,29 

Straw  for  lighting  up,  76 
Syracuse  Stove  Works,  melting  sheet 
of,  218 


36o 


INDEX. 


'TVA.BLB  of  diameter  and  area  of  blast 
1  pipes,  285 

•  speed  and  capacities  of 
blowers  as  applied  to 
cupolas,  309 

standard  foundry  blowers 
driven   by   pulley;    di- 
mensions in  inches,  319 
showing  the  necessary  increase 
in  diameter  for  the  different 
lengths  of  blast  pipes,  283 
Taking  off  the  blast  during  a  heat, 

276-299 

Tank  or  reservoir  cupola,  167-170 
Tanks,  use  of,  in  England,  169 
Tap-hole,  16,  17 

chilling  of  slag  in  the,  75 
closing  up  of  the,  with  slag,  339 
indication  of  the  melting  by  the 

flow  of  iron  from  the,  88,  89 
skill  of  the  melter  seen  at  the,  98 
mode  of  forming,  71 
preventing  the  cutting  of,  73 
reducing  the  size' of  the,  87,  88 
sizes  of,  73 
too  long,  effect  of,  72 
Tap-holes,  locating  the,  17,  73,  74 
Tap,  making  a,  when  iron  is  handled 

in  large  ladles,  87 
mode  of  making  the,  96,  97 
Tapping  and  stopping  in,  96-98 

bar,  explosion  of  iron  caused  by, 

258 
Tapping  bars,  92,  93 

burning  up  the,  341 
Tin  deposited  upon  iron,  recovery  of, 

225 

effect  of,  on  iron,  227 
-plate  scrap,  342 

cost  of  melting,  342 
cupola  for  melting,  227, 

228 

doctoring  metal  from,  227 
experiments  in  melting, 

226,  227 
fluxing  of,  228 
gray  metal  from,  226 
loss  of  metal  in  melting, 

342 
melting  of,  in  a  cupola, 

225-229 

preparation  of,  for  melt- 
ing, 225 
quality  of  metal    from, 

225,  226 

Treat,  C.  A.,  remarks  of,  344 
Triangular  tuyere,  39 
Trompe,  294 


Trucks  for  removing  the  dump,  100 
Truesdale  reducing  tuyere,  37,  38 
Tuyere  area,  combined,  of  a  cupola, 

49,50 

Blakeney,  35,36 
bottom,  46-49 
boxes,  19,  56,57 
Cheuney,  42 
Colliau,  41 

continuous  slot,  34,  35 
Doherty,  33,  34 
double,  42,  43 
expanded,  32,  33 
expanding,  297 
Greiner,  45 
horizontal  and  vertical  slot,  36, 37 

slot,  34 

invention,  epidemics  of,  30,  31 
Lawrence  reducing,  38,  39 
Mackenzie,  34,  85 
outlet  area  of  a,  297 
oval,  32 
reversed  T,  37 
round,  31,32 
sheet  blast,  34 
triangular,  26,  39 
Truesdale  reducing,  37,  38 
vertical  slot,  37 
water,  40,  41 
Whiting,  41 
Tuyeres,  18-20 

"  adjustable,  45,  46 
air   chamber   for  supplying  the, 

with  blast,  14 
center  blast,    experiments  with, 

298,  299 
connecting  blast  pipes  direct  with, 

from  a  belt  air  chamber, 286-290 
connection  of,  with  the  blower,  5 
consumption  of  fuel  under  the, 

50,51 

cupola,  30-57 
destruction  of  the  lining,  at  and 

below  the,  110 

direct  delivery  of  blast  to,  284 
fuel  under  the,  121,  122,  334 
general   improvement   made  in, 

341 
height  of,  50-53 

above   sand  bottom,  19, 

20,  333,  334 
high,  341 

reason  in  favor  of,  51 
increase  in  the  melting  capacity 

by  two  or  three  rows  of  21 
liability  of,  to  be  closed,  50 
location  of,  18,  19 
low,  122,  123 


INDEX. 


361 


Tuyeres,  number  of,  in  a  cupola,  2, 

18,  19,  54,  55 

placing  of,  in  a  cupola,  20,  21 
poking  the,  89 
projection  or  hump  on  the  lining 

over  the,  102 
shape  of,  19.  55 
size  of,  49,  50 
small,  objection  to,  49 
theory  of  preventing  iron  from 

running  into  the,  102 
three  rows  of,  43-45 
to  improve  the  quality  of  the  iron, 

55,56 

triangular,  297 
two  rows  of,  42,  43 

or  more  rows  of,  20,  21 
vertical  slot,  297 
very  best  way  of  connecting  blast 

pipes  with,  288-290 


VERTICAL  blower  and  engine  on 
same  bed  plate,  326 
slot  tuyere,  37 

Voisin,  bottom  tuyere  used  by,  48 
Voisin's  cupola,  161-163 

double    tuyere    used  in, 
42 


WARMING  up  a  cupola,  248-250 
Waste  heat  from  a  cupola, 274,275 

utilization  of,  12,  13 
Water  blast,  294 

cylinder  blast,  294 
gauges,  292 
tuyere,  40,  41 


West,  Thomas  D.,  experiments  with 
the  bottom 
tuyere  by, 
48,49 

with       the 

center  blast 

tuyere,  299 

West  Troy  Stove  Works,  bad  melting 

at  a,  242-248 
Whiting  cupola,  196-198 

Foundry  Equipment  Co.,  Chicago, 

tuyere  manufactured  by  the,  41 

Wilbraham-Baker  Blower  Co.,  blower 

built  by  the,  314-321 
Wood  and  coal,  bad  melting  caused 

by,  250,  251 

arranging  the,  for  lighting  up,  76 
for  lighting  up,  340 
Woodward's  steam-jet  cupola,  163-167 
double  tuy- 
ere   used 
in,  42 

7  INC,  effect  of,  on  the  fire  in  the 

LJ  cupola,  227 

Zone,  melting,  77,  123-129 

burning  away  of  the  lining 

at  the,  110 
depth  of,  125 

determination  of  the  loca- 
tion of  the,  123,335 
of  the  top  of,  335, 336 
development  of  the,  129 
rilling  in  the  lining  at  the, 

106, 107 

location  of  the,  77 
raising  and  lowering  the, 
120,123 


The  Largest  and  Most  Reliable  Foundry  Supply  House  in  the  World. 


TheS.ObermayerCo, 

manufactures  "  everything  you  need  in  your  foundry/' 

Cincinnati,  O.,  U.  5.  A.,  and  Chicago,  111.,  U.  S.  A. 

Cable  address  "  Esso."    Use  A.  B.  C.  code. 


Estimates  given  on  complete  Brass,  Iron  or 
Steel  Foundries. 


IMPORTERS   AND   REFINERS 

EAST  INDIA  PLUMBAGO,  SILVER,  LEAD,  GRAPHITE  and  TALC. 


General  and  special  Catalogues  sent  on  application. 


Special  Attention  given  to  Export  Orders. 

Shippers;    Cupola    Blocks,    Fire    Brick    Moulding    Sands, 
Canister  and  Silica. 


SPECIAL    ARTICLES. 

Cupolas,  Crucibles,  Chaplets, 

Cranes,  Brushes,  Core  Wash^ 

Tumbling  Mills,  Riddles,  Heavy  Machinery  Facing, 

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Ladles,  Bituminous  Facing,  Sand  Sifting  Machines, 

Brass  Melting  Furnaces,  Core  Compound,  Pattern  Lumber,  Etc.,  Etc. 

Crucible  Tongs,  Snap  Flasks, 


J.  W.  PAXSON  CO., 

Quaker  City  Facing  Mills, 

IFHILAlDEl^FSIA, 


A  Train  of  Nine  Exhaust  Tumblers, 

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J.  W.  PAXSON  CO. 


J.  W.  PAXSON  CO., 

Manufacturers,  Philadelphia,  Fa. 


J.W.IRCo. 


Cupolas. 

Spark  Arresters. 

Linings. 

Blast  Pipe. 

Gates  and  Gauges. 

Mica  Schist. 

Cupola  Breast  and  Runner, 

Screen  Charging  Doors. 

Mica  for  Tuyeres. 

Cupola  Picks. 

Cupola  Fluxes. 

Ladles. 

Trucks  and  Turntables. 

Core  Ovens. 

Sand  Sifters. 

Sand  Grinders. 

Sand  Dryers. 

Rumblers  for  Iron  and  Brass. 

Wheelbarrows. 

Pig  Iron  Barrows. 

Core  Box  Machines. 

Crucible  Tongs. 

Coke  and  Coal  Baskets. 


Cramp's  Pneumatic  Rammer. 

Chain  and  Rope  Slings. 

Brass  Furnaces. 

Brass  Foundry  Drying  Stoves. 

Emery  Grinders. 

Brass  Founder's  Flasks. 

Hay  Rope  Machines. 

Foundry  Lamps. 

Magnetic  Separators. 

Power  Cleaning  Brushes. 

Sprue  Cutters. 

Skimming  Gates. 

Universal  Trimmers. 

Molding  Machines. 

Sand  Blast  Machines. 

Molder's  Tools. 

Foundry  Facings, 

Molding  Sand. 

Wire  and  Bristle  Brushes. 

Tinned  Chaplets, 

Snap  Flasks. 

Fire  Clay. 

Shovels  and  Riddles,  etc. 


i  i 

it 


FOR   CATALOCUE,-<^~- 

IT   CONTAINS 
VALUABLE   INFORMATION    FOR 

Iron,  Brass  or  Steel  Foundry, 


STURTEVANT 

PRESSURE  BLOWERS 


Made  with   MOTOR    DIRECT  Connected. 

Send  for  Illustrated  Catalogue  No.  Qq. 

B.  F.  STURTEVANT  CO., 

BOSTON,    MASS. 

131  Liberty  Street,  NEW  YORK.  135  N.  Third  St.,  PHILADELPHIA. 

16  S.  Canal  St.,  CHICAGO.  75  Queen  Victoria  St.,  LONDON. 

STOCK  CARRIED  AT  BRANCHES. 


The 


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FOR 


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MADE  IN  ALL  SIZES  AND  TYPES. 


Blower  on  Adjustable  Bed  with  Double  Enclosed  Engine. 


WE  ALSO  MANUFACTURE 

Heating  and  Ventilating  Apparatus  for 

Foundries  and  other  Industrial  Establishments, 
Steam  Engines,  Generating  Sets, 

Piping  for  Blast  and  Exhaust  Systems. 


Whifehead  Brothers  Company, 


DEALERS  IN 


Molding 
Sand 


FIRE  SAND, 
PHILADELPHIA  SAND- 
FRENCH  SAND, 
FIRE  CLAY,  KAOLIN, 
FOUNDRY  FACINGS 
and  SUPPLIES 
OF  ALL  KINDS. 
.LEAD  FACINGS 
A  SPECIALTY. 


Albany  Sand  for  Brass  and  Stove  Plate  Castings, 


537-39  West  27th  St., 
NEW  YORK. 

Providence  Office,  Buffalo  Office, 

42  S.  Water  Street.  70  and  72  Columbia  St. 


WORKS  AT 

CHEESEQUAKE  CREEK,  N.  J.  CEDAE  HILL,  1ST.  Y. 

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RARITAN  RIVER,  N.  J.  CLINTON  POINT,  N.  Y. 

SOUTH  AMBOY,  N.  J.  ATHENS,  N.  Y. 

WAREHAM,  MASS.  COEYMANS,  N.  Y. 

CENTRE  ISLAND,  L.  I.  WILLOW  SPRINGS,  N.  Y. 

WATERFORD,  N.  Y.  POUGHKEEPSIE,  N.  Y. 

ALBANY,  N.  Y.  CRESCENT,  N.  Y. 


The  Green  Rotary  Pressure  Blower. 


L 


Working  parts  are  two  perfectly  balanced  impellers,  mounted 
on  the  best  steel  shafts,  running  in  bronze  bushes,  detachable 
journal  bearings,  cut  gearing  at  both  ends  of  the  Blower  enclosed 
in  oil-tight  casing. 

Weighs  less,  occupies  less  space,  costs  less  for  freight,  than 
any  other  POSITIVE  BLOWER  in  existence. 


FOUNDRY  BLOWERS 

High  Pressure  Blowers. 

GAS  EXHAUSTERS 

Exhausters  for  Hot  Gases. 

The  GREEN  gives  the  Host  Value  for  a  $. 

Wilbraham  Baker  Blower  Co., 

2518  Frankford  Ave.,  Philadelphia,  Pa. 


Sole  Agents  for  Mining  and  Smelting  Industries, 
FRASER  &  CHALflERS,  Inc.,  CHICAGO,  ILL.,  and  Branch  Houses. 


P.  H.  &  F.  M.  ROOTS  CO, 

109  Liberty  Street,  N.  Y.  Connersville,  Ind. 

Vandergrift  Building,  Pittsburg,  Pa. 


MANUFACTURERS   OF 


ROTARY  BLOWERS, 

Unrivaled.    The  Standard. 

Steam  Driven.     Electrically  Driven. 

Minimum  of  Friction.      Maximum  of  Efficiency. 


OVER   FORTY   YEARS'  EXPERIENCE. 


MORE  THAN  3O,OOO  SOLD. 


SEND  FOR  CATALOGUE. 


IN  THE  PLUMBAGO  LINE  WE  HAVE  FOUR  WINNERS. 

X  Plumbago-Pure  Ceylon 
Corona  Plumbago 

C.  F.  M.  Founders  Perfect  Wash 
send  for  Corona  Wash. 

Free  Sample. 


Manufactured  only  by 

The  Cleveland  Facing  Mill  Co, 

Foundry  Facings  and  Supplies, 
CLEVELAND,  O. 


OF 


fractal  and  Scientific 

PUBLISHED  BY 

HENRY  CAREY  BAIRD  &  Co, 


INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS. 

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AMATEUR  MECHANICS'  WORKSHOP: 

A  treatise  containing  plain  and  concise  directions  for  the  manipula- 
tion of  Wood  and  Metals,  including  Casting,  Forging,  Brazing, 
Soldering  and  Carpentry.  By  the  author  of  the  "  Lathe  and  Its 
Uses."  Seventh  edition.  Illustrated.  8vo.  .  .  .  $2.50 

ANDES. — Animal  Fats  and  Oils: 

Their  Practical  Production.  Purification  and  Uses;  their  Properties, 
Falsification  and  Examination.  62  illustrations.  8vo.  .  $4.00 

ANDES. — Vegetable  Fats  and  Oils: 

Their  Practical  Preparation,  Purification  and  Employment;  their 
Properties,  Adulteration  and  Examination.  94  illustrations.  8vo. 

$4-00 

ARLOT. — A  Complete  Guide  for  Coach  Painters : 

Translated  from  the  French  of  M.  ARLOT,  Coach  Painter,  for 
eleven  years  Foreman  of  Painting  to  M.  Eherler,  Coach  Maker, 
Paris.  By  A.  A.  FESQUET,  Chemist  and  Engineer.  To  which  is 
added  an  Appendix,  containing  Informs^"  >-esoecting  the  Materials 
;»nd  the  Practice  of  Coach  and  Car  Painting  . — d  Varnishing  in  the 
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4RMENGAUD,  AMOROUX,  AND  JOHNSON.— The  Practi- 
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chinist's  and  Engineer's  Drawing  Companion  : 
Forming  a  Complete  Course  of  Mechanical  Engineering  and  Archi- 
tectural Drawing.  From  the  French  of  M»  Armengaud  the  elder, 
Prof,  of  Design  in  the  Conservatoire  of  Arts  and  Industry,  Paris,  and 
MM.  Armengaud  the  younger,  and  Amoroux,  Civil  Engineers.  Re- 
written and  arranged  with  additional  matter  and  plates,  selections  from 
and  examples  of  the  most  useful  and  generally  employed  mechanism 
of  the  day.  By  WILLIAM  JOHNSON,  Assoc.  Inst.  C.  E.  Illustrated 
fey  fifty  folio  steel  plates,  and  fifty  wood-cuts.  A  new  edition,  410,, 

elotb $6.00 

ARMSTRONG.— The  Construction  and  Management  of  Steasn 

Boilers  : 

By  R.  ARMSTRONG,  C.  E.  With  an  Appendix  by  ROBERT  MALLET, 
€.  E.f  F.  R.  S.  Seventh  Edition.  Illustrated.  I  vol.  I2mo.  .60 

ARROWSMITH.— Paper-Hanger's  Companion : 
A  Treatise  in  which  the  Practical  Operations  of  the  Trade  are 
Systematically  laid  down :  with  Copious  Directions  Preparatory  to 
Papering;  Preventives  against  the  Effect  of  Damp  on  Walls;  the 
various  Cements  and  Pastes  Adapted  to  the  Several  Purposes  01 
the  Trade ;  Observations  and  Directions  for  the  Panelling  and 
Ornamenting  of  Rooms,  etc.  By  JAMES  ARROWSMITH.  I2mo., 
cloth  . $1.00 

*SHTON.— The  Theory  and  Practice  of  the  Art  of  Designing 

Fancy  Cotton  and  "Woollen  Cloths  from  Sample  : 
Giving  full  instructions  for  reducing  drafts,  as  well  as  the  methods  of 
spooling  and  making  out  harness  for  cross  drafts  and  finding  any  re- 
quired reed;  with  calculations  and  tables  of  yarn.  By  FREDERIC  T. 
ASHTON,  Designer,  West  Pittsfield,  Mass.  With  fifty-two  illustrations. 
One  vol.  folio  .  .  .  .  .  .  .  .  #5-°° 

ASKINSON. — Perfumes  and  their  Preparation  : 

A  Comprehensive  Treatise  on  Perfumery,  containing  Complete 
Directions  for  Making  Handkerchief  Perfumes,  Smelling-Salts, 
Sachets,  Fumigating  Pastils ;  Preparations  for  the  Care  of  the  Skin, 
the  Mouth,  the  Hair;  Cosmetics,  Hair  Dyes,  and  other  Toilet 
Articles.  By  G.  W.  ASKINSON.  Translated  from  the  German  by  IsiDOR 
FURST.  Revised  by  CHARLES  RICE.  32  Illustrations.  8vo.  $3.00 

BRONGNIART. — Coloring  and  Decoration  of  Ceramic  Ware. 

8vo .  $2.00 

BAIRD.— The  American  Cotton  Spinner,  and  Manager's  and 
Carder's  Guide: 

A  Practical  Treatise  on  Cotton  Spinning ;  giving  the  Dimensions  and 
Speed  of  Machinery,  Draught  and  Twist  Calculations,  etc.;  with 
notices  of  recent  Improvements:  together  with  Rules  and  Examples 
KM-  making  changes  in  the  sizes  and  numbers  of  Roving  and  Yarn. 
Compiled  from  the  papers  of  the  late  ROBERT  H.  BAIRD.  I2mo. 


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BAIRD.— Standard  Wages  Computing  Tables : 

An  Improvement  in  all  former  Methods  of  Computation,  so  arranged 
that  wages  for  days,  hours,  or  fractions  of  hours,  at  a  specified  rate 
per  day  or  hour,  may  be  ascertained  at  a  glance.     By  T.  SPANGLER 
BAIRD.     Oblong  folio        .......         $5.00 

BAKER.— Long-Span  Railway  Bridges  : 

Comprising    Investigations    of    the    Comparative    Theoretical    and 
Practical    Advantages   of  the  various  Adopted   or   Proposed    Type 
Systems  of  Construction ;  with  numerous  Formulae  and  Tables.     By 
B.  BAKER.     I2mo.  .         .......        #1.00 

BAKER. — The  Mathematical  Theory  of  the  Steam-Engine : 

With   Rules  at  length,  and  Examples  worked  out   for  the  use  of 

Practical   Men.     By  T.   BAKER,   C.   E.,  with  numerous  Diagrams. 

Sixth  Edition,  Revised  by  Prof.  J.  R.  YOUNG.     I2mo.          .  75 

BARLOW.— The    History    and    Principles    of    Weaving,   by 

Hand  and  by  Power: 

Re-printed,  with   Considerable  Additions,  from  "  Engineering,"  with 
a  chapter  on  Lace-making  Machinery,  reprinted  from  the  Journal  of 
the  "Society  of  Arts."    By  ALFRED  BARLOW.   With  several  hundred 
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BARR. — A  Practical  Treatise  on  the  Combustion  of  Coal: 
Including  descriptions  of  various  mechanical  devices  for  the  Eco- 
nomic Generation  of  Heat  by  the  Combustion  of  Fuel,  whether  solid, 
liquid  or  gaseous.    8vo.     .......         $2.50 

BARR. — A  Practical  Treatise  on  High  Pressure  Steam  Boilers : 
Including  Results  of  Recent  Experimental  Tests  of  Boiler  Materials, 
together  with  a  Description  of  Approved   Safety  Apparatus,  Steam 
Pumps,  Injectors  and  Economizers  in  actual  use.     By  WM.  M.  BARR. 
204  Illustrations.     8vo.      .  .....         $3.60 

8AUERMAN. — A  Treatise  on  the  Metallurgy  of  Iron : 
Containing  Outlines  of  the  History  of  Iron  Manufacture,  Methods  of 
Assay,  and  Analysis  of  Iron  Ores,  Processes  of  Manufacture  of  Iron 
and  Steel,  etc.,  etc.     By  H.  BAUERMAN,  F.  G.  S.,  Associate  of  the 
Royal  School  of   Mines.      Fifth    Edition,    Revised    and    Enlarged. 
Illustrated  with  numerous  Wood  Engravings  from  Drawings  by  J.  B. 
JORDAN.     I2mo.       ........        $2.oc 

BRANNT.— The  Metallic  Alloys:  A  Practical  Guide 

For  the  Manufacture  of  all  kinds  of  Alloys,  Amalgams,  and  Solders, 
used  by  Metal- Workers;  together  with  their  Chemical  and  Physical 
Properties  and  their  Application  in  tlie  Arts  and  the  Industries;  with 
an  Appendix  on  the  Coloring  of  Alloys  and  the  Recovery  of  Waste 
Metals.  By  WILLIAM  T.  BRANNT.  34  Engravings.  A  New,  Re- 
vised, and  Enlarged  Edition.  554  pages.  8vo.  .  .  $4.50 
BEANS. — A  Treatise  on  Railway  Curves  and  Location  of 

Railroads : 

By  E.  W.  BEANS,  C.  E.     Illustrated.     I2mo.     Tucks        .         $1.50 
BECKETT. — A  Rudimentary  Treatise  on  Clocks,  and  Watches 

and  Bells  : 

By  Sir  EDMUND  BECKETT,  Bart.,  LL.  D.,  Q.  C.  F.  R.  A.  S.  With 
numerous  illustrations.  Seventh  Edition,  Devised  and  Enlarged. 
|i.8o 


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BELL. — Carpentry  Made  Easy: 

Or,  The  Science  and  Art  of  Framing  on  a  New  and  Improved 
System.  With  Specific  Instructions  for  Building  Balloon  Frames,  Barn 
Frames,  Mill  Frames,  Warehouses,  Church  Spires,  etc.  Comprising 
also  a  System  of  Bridge  Building,  with  Bills,  Estimates  of  Cost,  and 
valuable  Tables.  Illustrated  by  forty-four  plates,  comprising  nearly 
200  figures.  By  WILLIAM  E.  BELL,  Architect  and  Practical  Builder. 
8vo.  .  • $5.00 

BEMROSE.— Fret-Cutting  and  Perforated  Carving  : 

With  fifty-three  practical  illustrations.  By  W.  BEMROSE,  JR.  I  vol. 
quarto  ..........  $2.50 

BEMROSE. — Manual  of  Buhl-work  and  Marquetry: 

With  Practical  Instructions  for  Learners,  and  ninety  colored  designs 
By  W.  BEMROSE,  JR.  I  vol.  quarto  ....  $3.00 

BEMROSE.— Manual  of  Wood  Carving: 

With  Practical  Illustrations  for  Learners  of  the  Art,  and  Original  and 
Selected  Designs.  By  WILLIAM  BEMROSE,  JR.  With  an  Intro- 
duction by  LLEWELLYN  JEWITT,  F.  S.  A.,  etc.  With  128  illustra- 
tions, 410.  .........  $2.50 

BILLINGS.— Tobacco : 

Its  History,  Variety,  Culture,  Manufacture,  Commerce,  and  Various 
Modes  of  Use.  By  E.  R.  BILLINGS.  Illustrated  by  nearly  200 
engravings.  8vo.  .  .  .  .  .  .  .  .  $3-°° 

BIRD. — The  American  Practical  Dyers'  Companion: 
Comprising  a  Description  of  the  Principal  Dye-Stuffs  and  Chemicals 
usea  in  Dyeing,  their  Natures  and  Uses;  Mordants,  and  How  Made; 
with  the  best  American,  English,  French  and  German  processes  for 
Bleaching  and  Dyeing  Silk,  Wool,  Cotton,  Linen,  Flannel,  Felt. 
Dress  Goods,  Mixed  and  Hosiery  Yarns,  Feathers,  Grass,  Felt,  Fur, 
Wool,  and  Straw  Hats,  Jute  Yarn,  Vegetable  Ivory,  Mats,  Skins, 
Furs,  Leather,  etc.,  etc.  By  Wood,  Aniline,  and  other  Processes, 
together  with  Remarks  on  Finishing  Agents,  and  Instructions  in  the 
Finishing  of  Fabrics,  Substitutes  lor  Indigo,  Water-Proofing  of 
Materials,  Tests  and  Purification  of  Water,  Manufacture  of  Aniline 
and  other  New  Dye  Wares,  Harmonizing  Colors,  etc.,  etc. ;  embrac- 
ing in  all  over  800  Receipts  for  Colors  and  Shades,  accompanied  by 
170  Dyed  Samples  of  Row  Materials  and  Fabrics.  By  F.  J.  BIRD, 
Practical  Dyer,  Author  of  "  The  Dyers'  Hand-Book. "  8vo.  j$7-5o 

BLINN. — A  Practical  Workshop  Companion  for  Tin,  Sheet- 
Iron,  and  Copper-plate  Workers  : 

Containing  Rules  for  describing  various  kinds  of  Patterns  used  by 
Tin,  Sheet-Iron  and  Copperplate  Workers;  Practical  Geometry; 
Mensuration  of  Surfaces  and  Solids ;  Tables  of  the  Weights  of 
Metals,  Lead-pipe,  etc.;  Tables  of  Areas  and  Circumference! 
of  Circles;  Japan,  Varnishes,  Lackers,  Cements,  Compositions,  etc., 
etc.  By  LEROY  J.  BLINN,  Master  Mechanic.  With  One  Hundred 
and  Seventy  Illustrations.  I2mo.  .....  $2.50 


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BOOTH.— Marble  Worker's  Manual: 

Containing  Practical  Information  respecting  Marbles  in  general,  theil 
Cutting,  Working  and  Polishing ;  Veneering  of  Marble  ;  Mosaics ; 
Composition  and  Use  of  Artiticial  Marble,  Stuccos,  Cements,  Receipts, 
Secrets,  etc.,  etc.  Translated  from  the  French  by  M.  L.  BOOTH. 
WithanAppendixconcerningAmerican  Marbles.  I2mo.,  cloth  $1.50 

BOOTH    and    MORFIT.— The    Encyclopaedia  of    Chemistry, 

Practical  and  Theoretical : 

Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine  and  Pharmacy.  By  JAMES  C.  BOOTH,  Melter 
and  Refiner  in  the  United  States  Mint,  Professor  of  Applied  Chem-' 
istry  in  the  Franklin  Institute,  etc.,  assisted  by  CAMPBELL  MORFIT/ 
author  of  "  Chemical  Manipulations,"  etc.  Seventh  Edition.  Com- 
plete in  one  volume,  royal  8vo.,  978  pages,  with  numerous  wood-cuts 
and  other  illustrations  .  .  .  .  .  .  $3«5° 

BRAM WELL.— The  Wool  Carder's  Vade-Mecum, 
A  Complete  Manual  of  the  Art  oi  Carding  Textile  Fabrics.     By  W, 
C.  BRAMWELL.     Third  Edition,  revised  and  enlarged.     Illustrated. 
Pp.  400.     lamo.        ........         $2.50 

BRAN  NT.— A    Practical   Treatise  on  Animal  and  Vegetable 

Fats  and  Oils  -• 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chem- 
ical Properties  and  Uses,  the  Manner  of  Extracting  and  Refining 
them,  and  Practical  Rules  tor  Testing  them;  as  well  as  the  Manufac- 
ture of  Artificial  Butter  and  Lubricants,  etc.,  with  lists  of  American 
Patents  relating  to  the  Extraction,  Rendering,  Refining,  Decomposing, 
and  Bleaching  of  Fats  and  Oils.  By  WILLIAM  T.  BRANNT,  Editor 
of  the  "  Tech  no- Chemical  Receipt  Book."  Second  Edition,  Revised 
and  in  a  great  part  Rewritten.  Illustrated  by  302  Engravings.  In 
Two  Volumes.  1304  pp.  8vo.  .....  $10.00 

BRANNT.— A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles  : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science ; 
comprising  the  Chemistry,  Raw  Materials,  Machines,  and  Utensils 
and  Various  Processes  of  Manufacture,  including  a  great  variety  of 
formulas.  Edited  chiefly  from  the  German  of  Dr.  C.  Deite,  A. 
Engelhardt,  Dr.  C.  Schaedler  and  others;  with  additions  and  lists 
of  American  Patents  relating  to  these  subjects.  By  WM.  T.  BRANNT. 
Illustrated  by  163  engravings.  677  pages.  8vo.  .  .  $7.50 

BRANNT.— India  Rubber,  Gutta  Percha  and  Balata : 

Occurrence,  Geographical  Distribution,  and  Cultivation,  Obtaining 
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portant,  and  most  useful  discoveries  in  Chemical  Technology,  and 
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chiefly  from  the  German  of  Drs.  Winckler,  Eisner,  Heintze,  Mier- 
zinski,  Jacobsen,  Koller,  and  Heinzerling,  with  additions  by  WM.  1i 
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I2mo.     495  pages     .  $2.09 

ROWN. — Five  Hundred  and  Seven  Mechanical  Movements: 
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Gearing,  Presses,  Horology  and  Miscellaneous  Machinery;  and  in- 
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BUCKMASTER.— The  Elements  of  Mechanical  Physics  : 
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BYLES.— Sophisms    of     Free    Trade    and    Popular    Political 

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6OWMAN.— The  Structure  of  the  Wool  Fibre  in  its  Relation 

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BYRNE.—  The  Practical  Model  Calculator: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work,  NaraJ 
Architect,  Miner  and  Millwright.  By  OLIVER  BYRNE.  8vo.,  nearly 
600  pages  .........  $3.00 

CABINET  MAKER'S  ALBUM  OF  FURNITURE; 
Comprising  a  Collection  of  Designs  for  various  Styles  of  Furniture. 
Illustrated  by  Forty-eight   Large  and  Beautifully   Engraved   Plates. 
Oblong,  8vo.     ........  ^1.50 

CALLINGHAM.—  Sign  Writing  and.  Glass  Embossing: 

A  Complete  Practical  Illustrated  Manual  of  the  Art.  By  JAMES 
CALLINGHAM.  121110.  .......  $1.50 

-AMPIN.  —  A  Practical  Treatise  on  Mechanical  Engineering: 
Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools,  Work. 
shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam- 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Irom 
Ores.  By  FPANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention  ;  with  a  Chapter  on  Explosions.  By  R» 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  Rules  for  Calculating  the 
Change  Wheels  for  Screws  on  a  Turning  Lathe,  and  for  a  Wheetj 
cutting  Machine.  By  J.  LA  NICCA.  Management  of  Steel,  Includ- 
ing Purging,  Hardening,  Tempering,  Annealing,  Shrinking  and 
Expansi  >n  ;  and  the  Case-hardening  of  Iron.  By  G.  EDF.  8vo. 
Illustrated  with  twenty-nine  plates  and  100  wood  engravings  $5'°* 


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CAREY.— A  Memoir  of  Henry  C.  Carey. 
By  DR.  WM.  ELDER,    With  a  portrait.     8vo.,  cloth         .        .        75 

CAREY.— The  Works  of  Henry  C.  Carey : 

Harmony  of  Interests  :    Agricultural,  Manufacturing  and  Commer- 
cial.    8vo.  .  $1.25 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  I  vol.  I2mo.  .  #2.00 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  $10.00 

Past,  Present  and  Future.     8vo $2.50 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  $7.50 
The  Slave-Trade,  Domestic  and  Foreign;  Why  it  Exists,  and 
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The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental  and  Moral  Science  (1872).  8vo.  .  .  $2.50 

CLARK. — Tramways,  their  Construction  and  Working : 

Embracing  o  Comprehensive  History  of  the  System.  With  an  ex- 
haustive analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air ;  a  description  of  the 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses. By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  I  vol.  8vo.  .  $7.50 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man- 
agement. By  ZERAH  COLBURN.  Illustrated.  I2mo.  .  $1.00 

COLLENS. — The  Eden  of  Labor;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"    "The  Historj 
of  Charity,"  etc.     I2mo.     Paper  cover,  $1.00;  Cloth          .         $I.2| 

COOLEY. — A  Complete  Practical  Treatise  on  Perfumery : 
Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Articler 
With   a  Comprehensive    Collection   of  Formulae.     By   ARNOLD  J 
COOLEY.    I2mo Jtl.f* 

COOPER.— A  Treatise  on  the  use  of  Belting  for  rtie  Traut 

mission  of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar- 
ranging Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten 
ings.  Examples  and  Rules  in  great  number  for  exhibiting  and  cal 
culating  the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Management  or 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  witn 
chapters  on  the  Transmission  of  Power  by  Ropes;  by  Iron  and 
Wood  Frictional  Gearing;  on  the  Strength  of  Belting  Leather;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  By 
JOHN  H.  COOPER,  M.  E.  8vo #3.50 

CRAIK.— The  Practical  American  Millwright  and  MUler. 
By  DAVID  CRAIK,  Millwright.     Illustrated  by  numerous  wood  en- 
l^ravings  and  two  folding  plates.     8vo $3-5° 


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CROSS.— The  Cotton  Yarn  Spinner: 

Showing  how  the  Preparation  should  be  arranged  for  Different 
Counts  of  Yarns  by  a  System  more  uniform  than  has  hitherto  been 
practiced;  by  having  a  Standard  Schedule  from  which  we  make  all 
our  Changes.  By  RICHARD  CROSS.  122  pp.  I2mo.  .  75 

CRISTIANI. — A  Technical  Treatise  on  Soap  and  Candles: 

With  a  Glance  at  the  Industry  of  Fats  and  Oils.  By  R.  S.  CRIS- 
TIANI, Chemist.  Author  of  "  Perfumery  and  Kindred  Arts."  Illus- 
trated by  176  engravings.  58 *  pages,  8vo. 

COURTNEY. — The  Boiler  Maker's  Assistant  in  Drawing, 
Templating,  and  Calculating  Boiler  Work  and  Tank 
Work,  etc. 

Revised  by  D.  K.  CLARK.     102  ills.     Fifth  edition.      .         .         80 
COURTNEY. — The  Boiler  Maker's  Ready  Reckoner : 

With  Examples  of  Practical  Geometry  and  Templating.  Revised  by 
D.  K.  CLARK,  C.  E.  37  illustrations.  Fifth  edition.  •  $1.60 

DAVIDSON.— A  Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling,  and  Sign- Writing: 

Containing  full  information  on  the  processes  of  House  Painting  in 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Piinciples  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  With  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A  DAVIDSON.  i2mo. 

$2.00 

DAVIES.— A  Treatise  on  Earthy  and  Other    Minerals   and 

Mining: 

By  I).  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  etc.  Illustrated  by 
76  Engravings.  I2mo.  ......  .  $500 

DAVIES. — A  Treatise  on  Met  lliferous  Minerals  and  Mining: 
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Quarries  and  Collieries.  Illustrated  by  148  engravings  of  Geological 
Formations,  Mining  Operations  and  Machinery,  drawn  from  the 
practice  of  all  parts  of  the  world.  Fifth  Edition,  thoroughly  Revised 
and  much  Enlarged  by  his  son,  E.  Henry  Davies.  I2mo  ,  524 
pages .  .  #5.00 

DAVIES. — A  Treatise  on  Slate  and  Slate  Quarrying: 

Scieniific,  Practical  and  Commercial.  By  D  C.  DAVI&S,  F.  G.  S., 
Mining  Engineer,  etc.  With  numerous  illustrations  and  folding 
plates.  I2mo $2.00 

DAVIS. — A  Practical  Treatise  on  the  Manufacture  of  Brick, 

Tiles  and  Terra-Cotta: 

Including  Stiff  Clay,  Dry  Clay,  Hand  Made,  Pressed  or  Front,  and 
Roadway  Paving  Brick,  Enamelled  Brick,  with  Glazes  and  Colors, 
Fire  Brick  and  Blocks,  Silica  Brick,  Carbon  Brick,  Glass  Pots,  Re- 


10          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

torts,  Architectural  Terra-Cotta,  Sewer  Pipe,  Drain  Tile,  Glazed  and 
Unglazed  Roofing  Tile,  Art  Tile,  Mosaics,  arid  Imitation  of  Intarsia 
or  Inlaid  Surfaces.  Comprising  every  product  of  Clay  employed  in 
Architecture,  Engineering,  and  the  Blast  Furnace.  With  a  Detailed 
Description  of  the  Different  Clays  employed,  the  Most  Modern 
Machinery,  Tools,  and  Kilns  used,  and  the  Processes  for  Handling, 
Disintegrating,  Tempering,  and  Moulding  the  Clay  into  Shape,  Dry- 
ing, Setting,  and  Burning.  By  Charles  Thomas  Davis.  Third  Edi- 
tion. Revised  and  in  great  part  rewritten.  Illustrated  by  261 
engravings.  662  pages  .......  $5.00 

DAVIS. — A  Treatise  on  Steam-Boiler  Incrustation  and  Meth- 
ods for  Preventing  Corrosion  and  the  Formation  of  Scale: 
By  CHARLES  T.  DAVIS.     Illustrated  by  65  engravings.     8vo.    $2.00 

DAVIS.-— The  Manufacture  of  Paper: 

Being  a  Description  of  the  various  Processes  for  the  Fabrication, 
Coloring  and  Finishing  of  every  kind  of  Paper,  Including  the  Dif- 
ferent Raw  Materials  and  the  Methods  for  Determining  their  Values, 
the  Tools,  Machines  and  Practical  Details  connected  with  an  intelli- 
gent and  a  profitable  prosecution  of  the  art,  with  special  reference  to 
the  best  American  Practice.  To  which  are  added  a  History  of  Pa- 
per, complete  Lists  of  Paper-Making  Materials,  List  of  American 
Machines,  Tools  and  Processes  used  in  treating  the  Raw  Materials, 
and  in  Making,  Coloring  and  Finishing  Paper.  By  CHARLES  T. 
DAVIS.  Illustrated  by  156  engravings.  608  pages,  8vo.  $6.00 

DAVIS. — The  Manufacture  of  Leather: 

Being  a  Description  of  all  the  Processes  for  the  Tanning  and  Tawing 
with  Bark,  Extracts,  Chrome  and  all  Modern  Tannages  in  General 
Use,  and  the  Currying,  Finishing  and  Dyeing  of  Every  Kind  of  Leather ; 
Including  the  Various  Raw  Materials',  the  Tools,  Machines,  and  all 
Details  of  Importance  Connected  with  an  Intelligent  and  Profitable 
Prosecution  of  the  Art,  with  Special  Reference  to  the  Best  American 
Practice.  To  which  are  added  Lists  of  American  Patents  (1884-1897) 
for  Materials,  Processes,  Tools  and  Machines  for  Tanning,  Currying, 
etc.  By  CHARLES  THOMAS  DAVIS.  Second  Edition,  Revised,  and 
in  great  part  Rewritten.  Illustrated  by  147  engravings  and  14  Sam- 
ples of  Quebracho  Tanned  and  Aniline  Dyed  Leathers.  8vo,  cloth, 
712  pages.  Price  ........  $7-5° 

DAWIDOWSKY— BRANNT.— A  Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilages, 
etc.: 

Based  upon  Actual  Experience.  By  F.  DAWIDOWSKY,  Technical 
Chemist.  Translated  from  the  German,  with  extensive  addition*, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM  T.  BRANNT,  Graduate  of  the  Royal  Agricultural  College 
of  Eldena,  Prussia.  35  Engravings.  I2mo.  .  .  .  $2.50 

DE  GRAFF.— The  Geometrical  Stair-Builders'  Guide: 
being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  its 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Steel 
Engravings ;   together  with  the  use  of  the  most  approved  principle? 
of  Practical  Geometry.     By  SIMON  DE  GRAFF,  Architect.      4*0. 

$2.00 


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DE  KONINCK— DIETZ.— A  Practical  Manual  of.  Chemical 

Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DB 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.  S.  G.,  M.  I.  C.  E.,  etc.  American 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A. 
FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  .  $1.50 

DUNCAN.— Practical  Surveyor's  Guide: 

Containing  the  necessary  information  to  make  any  person  of  com* 
mon  capacity,  a  finished  land  surveyor  without  the  aid  of  a  teacher 
By  ANDREW  DUNCAN.  Revised.  72  engravings,  214  pp.  I2mo.  $1.50 

DUPLAIS. — A  Treatise  on  the   Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grain,  Rice,  Potatoes,  Sorghum,  Aspho 
del,  Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy. 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aro- 
matic Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  the 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copiow 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc,0  etc,  Translated  and  Edited  from  the  French  of  MM.  DUPLAIS, 
By  M.  McKENNiE,  M.  D.  Illustrated.  743  pp.  8vo.  $15.00 

DYER  AND  COLOR-MAKER'S  COMPANION  : 

Containing  upwards  of  two  hundred  Receipts  for  making  Colors,  on 
the  most  approved  principles,  for  all  the  various  styles  and  fabrics  now 
in  evistence ;  with  the  Scouring  Process,  and  plain  Directions  for 
Preparing,  Washing-off,  and  Finishing  the  Goods.  I2mo.  $r  oo 

EIDHERR.— The  Techno-Chemical  Guide  to  Distillation: 
A  Hand-Book  for  the  Manufacture  of  Alcohol  and  Alcoholic  Liquors, 
including  the  Preparation  of  Malt  and  Compressed  Yeast.     Edited 
from  the  German  of  Ed.  Eidherr.    Fully  illustrated.    (In  preparation.) 

EDWARDS. — A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practical  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty-three  Engravings,  including  examples  of 
the  most  modern  Engines.  Third  edition,  thoroughly  revised,  with 
much  additional  matter.  1 2  mo.  414  pages  .  .  .  $2  oo 

EDWARDS. — Modern  American  Locomotive  Engines, 
Their  Design,  Construction  and  Management.     By  EMORY  EDWARDS, 
Illustrated  I2tno $2.OO 

EDWARDS.— The  American  Steam  Engineer: 
Theoretical  and  Practical,  with  examples  of  the  latest  and  most  ap- 
proved American  practice  in  the  design  and  construction  of  Steam 
Engines  and  Boilers.  For  the  use  of  engineers,  machinists,  boiler- 
makers,  and  engineering  students.  By  EMORY  EDWARDS.  Fully 
illustrated,  419  pages.  I2mo.  •  #2.50 


HENRY  CAREY  BAIRD  &  CO.'S   CATALOGUE. 


EDWARDS. — Modern  American  Marine  Engines,  Boilers,  ano 

Screw  Propellers, 

Their  Design  and  Construction.  Showing  the  Present  Praaice  ot 
the  most  Eminent  Engineers  and  Marine  Engine  Buildeis  in  the 
United  States.  Illustrated  by  30  large  and  elaborate  plates.  4to.  $5.00 

EDWARDS.— The  Practical  Steam  Engineer's  Guide 

In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam  Pumps,  Boilers,  Injectors, 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and  Steam 
Gauges.  For  the  use  of  Engineers,  Firemen,  and  Steam  Users.  By 
EMORY  EDWARDS.  Illustrated  by  119  engravings.  A2O  pages. 
121110.  ..........  $2  50 

EISSLER.— The  Metallurgy  of  Gold  : 

A  Practical  Treatise  on  the  Metallurgical  Treatment  of  Gold-Bear- 
ing  Ores,  including  the  Processes  of  Concentration  and  Chlorination, 
and  the  Assaying,  Melting,  and  Refining  of  Gold.  By  M.-  EISSLER. 
With  132  Illustrations.  I2mo $5.00 

EISSLER. — The  Metallurgy  of  Silver  : 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviation 
of  Silver  Ores,  including  the  Assaying,  Melting,  and  Refining  of 
Silver  Bullion.  By  M.  EISSLER.  124  Illustrations.  336  pp. 
I2mo.  ..........  $4.25 

ELDER. — Conversations  on  the  Principal  Subjects  of  Political 

Economy. 
By  DR.  WILLIAM  ELDER.     8vo $2.50 

ELDER. — Questions  of  the  Day, 

Economic  and  Social.     By  DR.  WILLIAM  ELDER.     8vo.     .      $3.00 

SRNL— Mineralogy  Simplified. 

Easy  Methods  of  Determining  and  Classifying  Minerals,  including 
Ores,  by  means  of  the  Blow]  ipe,  and  by  Humid  Chemical  Analysis, 
based  on  Professor  von  Kobell's  Tables  for  the  Determination  of 
Minerals,  with  an  Introduction  to  Modern  Chemistry.  By  HENRY 
ERNI,  A.M.,  M.D.,  Professor  of  Chemistry.  Second  Edition,  rewritten, 
enlarged  and  improved.  I2mo.  .... 

FAIRBAIRN.— The  Principles  of  Mechanism  and  Machinery 

of  Transmission  • 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pullevs, 
Strength  and  Proportions  of  Shafts,  Coupling  of  Shafts,  and  Engag- 
ing and  Disengaging  Gear.  By  SIR  WILLIAM  FAIRBAIRN,  Bart 
C.  E.  Beautifully  Illustrated  by  over  150  wood-cuts.  In  one 
Tolume,  I2tno $2.00 

FLEMING. — Narrow  Gauge  Railways  in  America. 
A  Sketch  of  their  Rise,  Progress,  and   Success.     Valuable  Statistics 
as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  etc.     By 
HOWARD  FLEMING.     Illustrated,  8vo $i  oo 

FORSYTH.— Book  of  Designs  for  Headstones,   Mural,  and 

oth&r  Monuments : 

Containing  78  Designs.  By  JAMES  FORSYTH.  With  an  Introduction 
•jy  CHARLES  BGUTELL,  M.  A.  4  to.,  cloth  .  .  $3-50 


HENRY    CAREY    BAIRD   &   CO.'S   CATALOGUE.        13 


FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu- 
facture of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine: 
Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pest,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical 
Manufacturer  of  Starch-Sugar.  Illustrated  by  58  engravings,  cover- 
ing every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  .  $3.50 

GARDNER.— The  Painter's  Encyclopaedia: 
Containing  Definitions  of  all  Important  Words  in  the  Art  of  Plain 
and  Artistic  Painting,  with  Details  of  Practice  in  Coach,  Carriage, 
Railway  Car,  House,  Sign,  and  Ornamental  Painting,  including 
Graining,  Marbling,  Staining,  Varnishing,  Polishing,  Lettering, 
Stenciling,  Gilding,  Bronzing,  etc.  By  FRANKLIN  B.  GARDNER. 
158  Illustrations.  I2ino.  427  pp.  ..'...  £2.00 

GARDNER. — Everybody's  Paint  Book: 

A  Complete  Guide  to  the  Art  of  Outdoor  and  Indoor  Painting.  38 
illustrations.  121110,  183  pp $l.oo 

GEE. — The   Jeweller's    Assistant  in  the    Art  of  Working  in 

Gold: 
A  Practical  Treatise  for  Masters  and  Workmen.      I2mo.      .       $3.00 

GEE.— The  Goldsmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting, and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste ;  Chemical  and  Physical  Properties  of  Gold ;  with  a  New 
System  of  Mixing  its  Alloys ;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  <.  .  $1.25 

GEE. — The  Silversmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of  Refining  ^.nd  Melting  the  Metal;  its 
Solders;  the  Preparation  of  Imitation  Alloys;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste  ;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 
Memoranda.  By  GEORGE  E.  GEE.  Illustrated.  I2mo.  Si. 25 

GOTHIC  ALBUM  FOR  CABINET-MAKERS: 

Designs  for  Gothic  Furniture.     Twenty-three  plates.     Oblong  $1.50 
aRANT. — A  Handbook  on  the  Teeth  of  Gears  : 
Their  Curves,  Properties,  and  Practical  Construction.     By  GEORGE 
B.  GRANT.     Illustrated.     Third  Edition,  enlarged.     8vo.          $\  oo 

CAREEN  WOOD.— Steel  and  Iron: 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolling- 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN- 
WOOD, F.  C.  S.  With  97  Diagrams,  536  pages.  I2mo.  £1.75 


14       HENRY   CAREY   BAIRD   &   CO.'S  CATALOGUE. 


GREGORY.— Mathematics  for  Practical  Men : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  OLINTHUS  GREGORY.  8vo.,  plates  #3.00 

GRISWOLD. — Railroad  Engineer's  Pocket  Companion  for  thi 

Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En 
gineers;  also  the  Art  of  Levelling  from  Preliminary  Survey  to  the 
Construction  of  Railroads,  intended  Expressly  for  the  Young  En- 
gineer, together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  I2mo.,  tucks #1.50 

GRUNER. — Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  o5 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  author's  sanction,  with  an  appendix,  by  L.  D 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

Hand-Book  of  Useful  Tables  for  the  Lumberman,  Farmet  and 

Mechanic : 

Containing  Accurate  Tables  of  Logs  Reduced  to  Inch  Board  Meas. 
ure,  Plank,  Scantling  and  Timber  Measure;  Wages  and  Rent,  by 
Week  or  Month;  Capacity  of  Granaries,  Bins  and  Cisterns;  Land 
Measure,  Interest  Tables,  with  Directions  for  Finding  the  Interest  on 
any  sum  at  4,  5,  6,  7  and  8  per  cent.,  and  many  other  Useful  Tables. 
32  mo.,  boards.  186  pages  ......  .25 

HASERICK.— The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleaching  and  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yami 
or  fabrics.  8vo.  ........  $7-5o 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  Hatter. 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  $1.2$ 

HERMANN. — Painting  on  Glass  and  Porcelain,  and  Enamel 

Painting: 

A  Complete  Introduction  to  the  Preparation  of  all  the  Colors  and 
Fluxes  Used  for  Painting  on  Glass,  Porcelain,  Enamel,  Faience  and 
Stoneware,  the  Color  Pastes  and  Colored  Glasses,  together  with  a 
Minute  Description  ot  the  Firing  ot  Colors  and  Enamels,  on  the 
Basis  of  Personal  Practical  Experience  of  the  Art  up  to  Date.  18 
illustrations.  Second  edition. $4.00 

HAUPT.— Street  Railway  Motors: 

With  Descriptions  and  Cost  of  Plants  and  Operation  of  the  Variou* 
Systems  now  in  Use.  I2mo.  $1-75 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         15 

HERZFELD.— The  Technical  Testing  of  Yarns  and  Textile 
Fabrics. 

69  illustrations.     8vo.       .         .  $4  oo 

HURST.— Lubricating  Oils,  Fats  and  Greases : 

Their  Origin,  Preparation,  Properties,  Uses  and  Analysis.  65  illus- 
trations. 8vo.  .  ...  $4  oo 

HURST.— Soaps: 

A  Practical  Manual  of  the  Manufacture  of  Domestic,  Toilet  and 
Other  Soaps.  66  illustrations.  8vo.  ....  $5.00 

HUGHES. — American  Miller  and  Millwright's  Assistant: 
By  WILLIAM  CARTER  HUGHES.     i2mo $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing  : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich ;  the  Royal  Military  College,  Sandhurst ;  the  Indian  Civil  En* 
gineering  College,  Cooper's  Hill  ;  Indian  Public  Works  and  Tele- 
graph Departments  ;  Royal  Marine  Liyht  Infantry  ;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 
examples.  Small  quartc «  $2.50 

JERV1S.— Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property ;  as  well  as  Railway  Managers,  Offi- 
cers, and  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  the 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  $2.oc 

KEENE.— A  Hand-Book  of  Practical  Gauging: 

For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla- 
tion, describing  the  process  in  operation  at  the  Custom-House  for 
ascertaining  the  Strength  of  Wines.  By  JAMES  B.  KEENE,  of  H.  M. 
Customs.  8vo. $1.00 

KELLEY. — Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 
By  HON.  WILLIAM  D.  KELLEY,  M.  C.     544  pages,  8vo.  .        $2.50 

KELLOGG. — A  New  Monetary  System  : 

The  only  means  of  Securing  the  respective  Rights  of  Labor  and 
Property,  and  of  Protecting  the  Public  from  Financial  Revulsions. 
By  EDWARD  KELLOGG.  i2mo.  Paper  cover,  $1.00.  Bound  in 
cloth $1.25 

KEMLO.— Watch- Repairer's  Hand-Book : 
Being  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apart. 
Putting  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  Foreign  Watches,  and  all  American  Watches.     By  F.  KEMLO, 
Practical  Watchmaker.     With  Illustrations.     I2mo.  .         $1.25 


16          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

KENTISH.— A  Treatise  on  a  Box  of  Instruments, 
And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Log* 
rithms,  including  Practical  Geometry,  Surveying,  Measuring  of  Tim- 
ber,  Cask  and  Malt  Gauging,  Heights,  and  Distances.     By  THOMA* 
KENTISH.     In  one  volume.     i2mo.  ....        $1.00 

KERL.— The  Assayer's  Manual  : 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.  By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines.  Translated  from  the  German  by 
WILLIAM  T.  BRANNT.  Second  American  edition,  edited  with  Ex- 
tensive Additions  by  F.  LYNWOOD  GARRISON,  Member  of  the 
American  Institute  of  Mining  Engineers,  etc.  Illustrated  by  87  en- 
gravings. 8vo $3>oc 

KICK.— Flour  Manufacture . 

A  Treatise  on  Milling  Science  and  Practice.  By  FREDERICK  KICK 
Imperial  Regierungsrath,  Professor  of  Mechanical  Technology  in  tht 
imperial  German  Polytechnic  Institute,  Prague.  Translated  from 
the  second  enlarged  and  revised  edition  with  supplement  l>y  II.  H. 
P.  POWLES,  Assoc.  Memb.  Institution  of  Civil  Engineers.  Illustrated 
with  28  Plates,  and  167  Wood-cuts.  367  pages.  8vo.  .  #10.00 

KINGZETT. — The   History,  Products,  and   Processes  of  the 

Alkali  Trade : 

Including  the  most  Recent  Improvements.  By  CHARLES  THOMAS 
VivnzF.TT.  Consulting  Chemist.  With  23  illustrations.  8vo.  $2.50 

KIRK. — The  Cupola  Furnace: 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foundry 
Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter,  Con- 
sulting Expert  in  Melting.  Author  of  "  The  Founding  of  Metals." 
Illustrated  by  78  engravings.  8vo.  379  pages.  .  .  $3-S° 

LANDRIN.— A  Treatise  on  Steel : 

Com  prising  its  Theory,  Metallurgy.  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.  From  the  French,  by  A.  A. 
FESQUET.  i2mo.  .....  ...  $2.50 

LANGBEIN. — A   Complete  Treatise  on  the  Electro-Deposi. 

tion  of  Metals  : 

Comprising  Electro-Plating  and  Galvnnoplastic  Operations,  the  De- 
position of  Metals  by  the  Contact  ar.d  Immersion  Processes,  the  Color- 
ing of  Metals,  the  Methods  of  Grinding  and  Polishing,  as  well  as 
Descriptions  of  the  Electric  Elements  Dynamo-Electric  Machines, 
Thermo-Piles  and  of  the  Materials  and  Processes  used  in  Every  De- 
partment of  the  Art.  From  the  German  of  DR.  GEORGE  LANGBEIN, 
with  additions  by  WM.  T.  BRANNT.  Third  Edition,  thoroughly  re- 
vised and  much  enlarged.  1 50  Engravings.  5  28  pages.  8vo.  $4.00 

LARDNER.— The  Steam-Engine : 

For  the  Use  of  Beginners.     Illustrated.     I2mo.    .         .         .         60 

LEHNER.— The  Manufacture  of  Ink: 

Comprising  the  Raw  Materials,  and  the  Preparation  df  Waiting, 
Copying  and  Hekiograph  Inks,  Safety  Inks,  Ink  Extracts  and  Pow- 
ders, etc.  Translated  from  the  German  of  SIGMUND  LEHNER,  with 
additions  by  WILLIAM  T.  BRANNT.  Illustrated.  I2mo.  #2.00 


HENRY   CAREY    BAIRD   &   ™D.'S   CATALOGUE.        17 

LARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide: 
A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  an4 
their  Alloys,  etc.;  to  \vn:ch  are  added  Recent  Improvements  in  the 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  Bj 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  U 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  New  edition, 
revised,  with  extensive  additions.  I2mo.  .  .  .  $2.50 

LEROUX. — A    Practical     Treatise    on    the    Manufacture    of 

Worsteds  and  Carded  Yarns  : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  the 
International  Jury,  and  of  the  Artisans  selected  by  the  Commute* 
appointed  by  the  Council  of  the  Society  of  Arts,  London,  on  Woolet 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni- 
versal Exposition,  1867.  8vo.  .  .  .  .  #5.00 

LEFFEL. — The  Construction  of  Mill-Dams  : 
Comprising  also  the  BuMding  of  Race  and  Reservoir  Embankment* 
and   Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Water 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo. $2'$G 

L.ESLIE. — Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thousand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  I2mo.  ........  $1.50 

LE  VAN. — The  Steam  Engine  and  the  Indicator: 

Their  Origin  and  Progressive  Development ;  including  the  Most 
Recent  Examples  of  Steam  and  Gas  Motors,  together  \\ith  the  Indi- 
cator, its  Principles,  its  Utility,  and  its  Application.  By  Wil.LlAM 
BARNET  LE  VAN.  Illustrated  by  205  Engravings,  chiefly  of  Indi- 
cator-Cards. 469  pp.  8vo.  ......  $4-°° 

LIEBER.— Assayer's  Guide  : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
the  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  Revised.  283  pp.  I2mo.  $1.50 

Ix>ckwood's  Dictionary  of  Terms  : 

Used  in  the  Practice  of  Mechanical  Engineering,  embracing  thos«j 
Current  in  the  Drawing  Office,  Pattern  Shop,  Foundry,  Fitting,  Turn-/ 
ing,  Smith's  and  Boiler  Shops,  etc.,  etc.,  comprising  upwards  of  Six* 
Thousand  Definitions.  Edited  by  a  Foreman  Pattern  Maker,  author 
of  "  Pattern  Making."  417  pp.  I2ino.  .  ,  .  #3.00 


18         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

LUKIN.— The  Lathe  and  Its  Uses  : 

Or  Instruction  in  the  Art  of  Turning  Wood  and  Metal.  Including 
a  Description  of  the  Most  Modern  Appliances  for  the  Ornamentation 
of  Plane  and  Curved  Surfaces,  an  Entirely  Novel  Form  of  Lathe 
for  Eccentric  and  Rose-Engine  Turning;  A  Lathe  and  Planing 
Machine  Combined;  and  Other  Valuable  Matter  Relating  to  the 
Art.  Illustrated  by  462  engravings.  Seventh  edition.  315  pages. 

8vo #4-25 

MAIN  and  BROWN. — Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And    Examination    Papers;    with    Hints    for    their   Solution.     By 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal   ""tfaval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.    I2mo.,  cloth  .       $1.00 
MAIN  and  BROWN.— The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.  MAIN,   M.  A.  F.  R.,   Ass't    S.    Professor    Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineer 
R.  N.,  attached  to  the  R.  N.  College.     Illustrated.     8vo.  . 
MAIN  and  BROWN.— The  Marine  Steam-Engine. 
By  THOMAS  J.  MAIN,  F.  R.  Ass't  S.  Mathematical  Professor  at  the 
Royal    Naval    College,   Portsmouth,  and    THOMAS    BROWN,   Assoc. 
Inst.  C.   E.,  Chief  Engineer  R.  N.     Attached  to  the  Royal  Naval 
College.     With  numerous  illustrations.     8vo. 
MAKINS.— A  Manual  of  Metallurgy: 

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rewritten  and  much  enlarged.  I2mo.,  592  pages  .  .  $3-OC 

WARTIN.  — Screw-Cutting  Tables,  for  the  Use  of  Mechanic*) 

Engineers  : 

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of  Screws  of  any  Required  Pitch ;  with  a  Table  for  Making  the  Uni 
versal  Gas-Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 
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N  1CHELL. — Mine  Drainage : 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under 
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MOLESWORTH.— Pocket-Book    of    Useful     Formulae     and 

Memoranda  for  Civil  and  Mechanical  Engineers. 
By  Gun, FORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident   Engineer  of  the  Ceylon  Railway.     Full- 
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HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          19 

I4OORE.— The   Universal  Assistant  and  the  Complete  Me- 
chanic : 

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Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
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MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks  : 
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Wood-Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas. 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyors^ 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork. 
By  ELWOOD  MORRIS,  C.  E.  8vo $i«5C 

MAUCHLINE.— The  Mine  Foreman's  Hand-Book 

Of  Practical  and  Theoretical  Information  on  the  Opening,  Venti- 
lating, and  Working  of  Collieries.  Questions  and  Answers  on  Prac- 
tical and  Theoretical  Coal  Mining.  Designed  to  Assist  Students  and 
Others  in  Parsing  Examinations  for  Mine  Foreman  ships.  By 
ROBERT  MAUCHLINE,  Ex-Inspector  of  Mines.  A  New,  Revised  and 
Enlarged  Edition.  Illustrated  by  114  engrarings.  8vo.  337 
Pages #3.75 

NAPIER.— A  System  of  Chemistry  Applied  to  Dyeing. 
By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Edi- 
tion. Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar  Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  on  Dyeing  and  Caiicq 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus- 
trated. .8vo.  422  pages  . $3.00 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formula,  foi 
finding  the  Discharge  of  Water  from  Orifices,  Notches, 
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Third  Edition,  with  Additions,  consisting  of  New  Formulae  for  the 
Discharge  from  Tidal  and  Flood  Sluices  and  Siphons ;  general  infor- 
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Supply  for  Towns  and  Mill  Power.  Bv  TOHN  NEVILLE.  C.  E.  M  R 
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NEWBERY.—  Gleanings     from     Ornamental     Art    of     ever> 

style : 

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Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
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exquisitely  drawn  Plates,  containing  many  hundred  examples.  B* 
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NICHOLLS.-The  Theoretical  and  Practical  Boiler- Maker  an<? 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor 
Foremen  a'vl  Working  Boiler-Makers.  Iron,  Copper,  and  Tinsstuth* 


*o         HENRY  CAREY  BAIRD  £  CO.'S  CATALOGUE. 

JLn-aughtsmen,  Engineers,  the  General  Steam-using  Public,  and  for  the 
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NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding: 
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Paper.     By  JAMES  B.  NICHOLSON.     Illustrated.  I2mo.,  cloth     $2.25 

NICOLLS.— The  Railway  Builder: 

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way Construction  and  Equipment.  By  WILLIAM  J.  NICOLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form 

r^  ORMANDY.— The  Commercial  Handbook  of  Chemical  An- 

alysis : 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  01 
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and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
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NORRIS. — A  Handbook  for  Locomotive    Engineers  and  Ma- 
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motives; Manner  of  Setting  Valves;  Tables  cf  Squares,  Cubes,  Areas, 
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NYSTROM; — A  New  Treatise  on  Elements  of  Mechanics : 
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accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me 
trology.     By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo.        $30* 

NYSTROM. — On  Technological  Education  and  the  Construc- 
tion of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  Inu 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi 
tional  matter.  Illustrated  by  seven  engravings.  I2mo.  .  $1.2, 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 
Containing  a  brief  account  of  all  the  Substances  and  Piocesses  it 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  Practical 
Receipts  and  Scientific  Information.  By  CHARLES  O'NEILL,  Analy- 
tical Chemist.  To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.  By  A.  A.  FF.SQUET, 
Chemist  and  Engineer.  With  an  appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867-  8vo., 
491  pages  .  $3.00 

ORTON. — Underground  Treasures'. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
of  ail  the  Useful  Minerals  within  the  United  States.  By  JAMES 
ORTON,  A.M.,  Late  Professor  of  Natural  History  in  Vassar  College, 
>J.  Y.;  Cor.  Mem.  of  the  Academy  of  Natural  Sciences,  Philadelphia, 
and  of  the  Lyceum  of  Natural  History,  New  York ;  author  of  the 
"Andes  and  the  Amazon,"  etc.  A  New  Edition,  with  Additions. 
Illustrated  - #i-<? 


HENRY    CAREY    BAIRD   &   CO.'S   CATALOGUE.        21 


OSBORN. — The  Prospector's  Field  Book  and  Guide. 

In  the  Search  For  and  the  Easy  Determination  of  Ores  and  Other 
Useful  Minerals.  By  Prof.  H.  S.  OSBORN,  LL.  D.  Illustrated  by  58 
Engravings.  I2mo.  Fourth  Edition.  Revised  and  Enlarged 

C899) $1.50 

OSBORN — A  Practical  Manual  of  Minerals,  Mines  and  Mm 

ing: 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and  Associations  of  the  Useful  Minerals;  their  Methods  of 
Chemical  Analysis  and  Assay ;  together  with  Various  Systems  of  Ex- 
cavating and  Timbering,  Brick  and  Masonry  Work,  during  Driving, 
Lining,  Bracing  and  other  Operations,  etc.  By  Prof.  H.  S.  OSBORN, 
LL.  D.,  Author  of  "  The  Prospector's  Field- Book  and  Guide."  171 
engravings.  Second  Edition,  revised.  8vo.  .  .  .  $4-5° 
OVERMAN.— Thu  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware,  of  Slt'el   and    Iron,   and   for    Men   of  Science   and   Art.     By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  lion,"  etc.     A  new,  enlarged,  and  revised   Edition.     By 
A.  A.  FESQU£T,  Chemist  and  Engineer.     I2mo.         .         .         $1.50 
OVERMAN.— The  Moulder's  and  Founder's  Pocket  Guide : 
A  Treatise  on  Moulding  and  P'ounding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow- 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues;  Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals;   Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.     By   FREDERICK  OVERMAN,.  M.  E.     A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
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ist and  Engineer.     Illustrated  by  44  engravings.     I2mo.    .         $2.OO 
PAINTER,  GILDER,  AND  VARNISHER'S  COMPANION. 
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ing, Graining,  Marbling,  Staining,  Sign  writing,  Varnishing,  Glass- 
staining,  and  Gilding  on  Glass;   together  with  Coach  Painting  and 
Varnishing,   and  the    Principles    of  the   Harmony  and  Contrast  of 
Colors.     Twenty-seventh  Edition.     Revised,  Enlarged,  and  in  great 
part  Rewritten.     By  WILLIAM  T.  BRANNT,  Editor  of  "  Varnishes, 
Lacquers,  Printing  Inks  and  Sealing  Waxes."      Illustrated.     395  pp. 

121110.  , $1  50 

PALLETT. — The  Miller's,  Millwright's,  and  Engineer's  Guide. 
Bv  HENRY  PALLETT.     Illustrated.     i2mo.       .        .        .        #2.00 


22         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

PERCY.— The  Manufacture  of  Russian  Sheet-Iron. 

By  JOHN  PERCY,  M.  D.,  F.  R.  S.     Paper.       ...         25  cts. 
PERKINS.— Gas  and  Ventilation: 

Practical  Treatise  on  Gas  and  Ventilation.    Illustrated.    I2mo.    $1.25 
PERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

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to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron ;  the  Thickness  of  the  Bar  Gauge 
in  decimals ;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  112  Ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 

$1.50 

POSSELT. — Recent  Improvements  in  Textile  Machinery  Re- 
lating to  Weaving  : 

Giving  the  Most  Modern  Points  on  the  Construction  of  all  Kinds 
of  Looms,  Warpers,  Beamers,  Slashers,  Winders,  Spoolers,  Reeds, 
Temples,  Shuttles,  Bobbins,  Heddles,  Heddle  Frames,  Tickers, 
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POSSELT. — Technology  of  Textile  Design: 

The  Most  Complete  Treatise  on  the  Construction  and  Application 
of  Weaves  for  all  Textile  Fabrics  and  the  Analysis  of  Cloth.  By  E. 

A.  Posselt.     1,500  illustrations.     410 $5-OO 

POSSELT.— Textile  Calculations: 

A  Guide  to  Calculations   Relating  to  the  Manufacture  of  all  Kinds 
of  Yarns  and  Fabrics,  the  Analysis  of  Cloth,  Speed,  Power  and  Belt 
Calculations.     By  E.  A.  POSSELT.     Illustrated.     410.        .         $2.00 
REGNAULT. — Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  $6.00 
RICHARDS.— Aluminium  : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illust.  Third  edition,  enlarged  and  revised  (1895)  •  $6-°° 
RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting  : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors:  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessary  Apparatus  and  Directions  for  its  Use;  Dryers;  the 
Testing.  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
RIFFAULT,  VERGNAUD,  and  TOUSSAINT.  Revised  and  Edited  by  M. 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  23 


F.  MALEPEYRE.  Translated  from  the  French,  by  A.  A.  FESQUny 
Chemist  and  Engineer.  Illustrated  by  Eighty  engravings.  In  one 
vol.,  8vo.,  659  pages  .......  $5.00 

ROPER.— A  Catechism  of  High- Pressure,  or  Non-Condensing 

Steam-Engines : 

Including  the  Modelling,  Constructing,  and  Management  of  Steam- 
Engines  and  Steam  Boilers.  With  valuable  illustrations.  By  STE- 
PHEN ROPER.  Engineer.  Sixteenth  edition,  revised  and  enlarged. 
1 8mo.,  tucks,  gilt  edge  .  .  .  .  .  .  $2.oc 

KOPER.— Engineer's  Handy-Book: 

Containing  a  full  Explanation  of  the  Steam-Engine  Indicator,  and  its 
Use  and  Advantages  to  Engineers  and  Steam  Users.  With  Formulae 
for  Estimating  the  Power  of  all  Classes  of  Steam- Engines;  also, 
Facts,  Figures,  Questions,  and  Tables  for  Engineers  who  wish  to 
qualify  :hemst-lve>  for  the  United  States  Navy,  the  Revenue  Service, 
the  Mercantile  Marine,  or  to  take  charge  of  the  Better  Class  of  Sta- 
tionary Steam-Engines.  Tenth  edition.  l6mo..  690  pages,  tucks, 
gi!t  edSe $3-50 

ROPER.— Hand-Book  of  Land  and  Marine  Engines  : 
Including  the   Modelling,  Construction,   Running,  and   Management 
of  Lain'  nml  Marine  Engines  and  Boilers.     With  illustrations,     rfy 
STEPHEN  ROPER,  Engineer.    Sixth  edition.     I2mo.,tx'cks,  gilt  edge. 

#3-5° 

ROPER.— Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion, Management,  and  Running  of  Locomotives.  By  STEPHEN 
ROPER.  Eleventh  edition.  i8mo.,  tucks,  gilt  edge  .  $2.$<k 

ROPER.— Hand-Book  of  Modern  Steam  Fire-Engines. 
With  illustrations.     By  STEPHEN  ROPER,  Engineer.     Fourth  edition, 
I2mo.,  tucks,  gilt  edt;e       .......         $3.50 

ROPER. — Questions  and  Answers  for  Engineers. 

This  little  book  contains  all  the  Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or 
dinary  intelligence  may  commit  them  to  memory  in  a  short  time.  By 
STEPHEN  ROPER,  Engineer.  Third  edition  .  .  .  $2.00 

ROPER.— Use  and  Abuse  of  the  Steam  Boiler. 

By  STEPHEN  ROPER,  Engineer.  Eighth  edition,  with  illustrations. 
i8mo.,  tucks,  gilt  edge $2.00 

ROSE.— The  Complete  Practical  Machinist : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools. 
Tool  Grinding,  Marking  out  Work,  Machine  Tools,  etc.  By  JOSHUA 
ROSE.  391;  Engravings.  Nineteenth  Edition,  greatly  Enlarged  with 
New -and  Valuable  Matter.  i2mo.,  504  pages.  .  .  $2.50 

ROSE. — Mechanical  Drawing  Self-Taught: 

Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Instruments,  Elementary  Instruction  in  Practical  Mechanical  Draw- 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


ing,  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
Motions,  Engines  and  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  330  engravings.  8vo  ,  313  pages  ....  #4.00 

ROSE.—  The  Slide-  Valve  Practically  Explained: 

Embracing  simple  and  complete  Practical  Demonstrations  of  thv 
operation  of  each  element  in  a  Slide-valve  Movement,  and  illustrat- 
ing the  effects  of  Variations  in  their  Proportions  by  examples  care- 
fully  selected  from  the  most  recent  and  successful  practice.  By 
JOSHUA  ROSE,  M.  E.  Illustrated  by  35  engravings  .  $1.00 

ROSS.  —  The  Blowpipe  in  Chemistry,  Mineralogy  and  Geology: 
Containing  all  Known  Methods  of  Anhydrous  Analysis,  many  Work- 
ing Examples,  and  Instructions  for  Making  Apparatus.  By  LIEUT.- 
COLONEL  W.  A.  Ross,  R.  A.,  F.  G.  S.  With  120  Illustrations. 


SHAW.—  Civil  Architecture  : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building,  con. 
taining  the  Fundamental  Principles  of  the  Art.  By  EDWARD  SHAW, 
Architect.  To  which  is  added  a  Treatise  on  Gothic  Architecture,  etc. 
By  THOMAS  W.  SILLOWAY  and  GEORGE  M.  HARDING,  Architects. 
The  whole  illustrated  by  102  quarto  plates  finely  engraved  on  copper. 
Eleventh  edition.  4to.  .......  #6.00 

SHUNK.  —  A  Practical  Treatise  on  Railway  Curves  and  Loca- 

tion, for  Young  Engineers. 
By  W.  F.  SHUNK,  C.  E.     121110.    Full  bound  pocket-book  form  $2.00 

SLATER.  —  The  Manual  of  Colors  and  Dye  Wares. 
By  J.  W.  SLATER.     i2mo  .......  .     #3-°° 

SLOAN.  —  American  Houses  : 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  engravings,  with  descriptive  references.  By  SAMUEL 
SLOAN,  Architect.  8vo.  .  .  .  .  .  .  -75 

SLOAN.  —  Homestead  Architecture: 

Contain  1  1:£  Forty  Designs  for  Villas,  Cottages,  and  Farm-houses,  with 
Essays  on  Stylw,  Construction,  Landscape  Gardening,  Furniture,  etc., 
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Architect.  8vo.  .  .  •  <  .  .  .  .  $2.50 

SLOANE.—  Ho.re  Experiments  m  Science. 

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SULLIVAN.— Protection  to  Native  Industry. 
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SHERRATT.— The  Elements  of  Hand-Railing: 

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FHAUSING.— The  Theory  and  Practice  of  the  Preparation  of 

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HENRY  CAREY  BAIRB  &  CO.'S  CATALOGUE.          27 

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Illustrated  by  twenty-one  plates.  4to.  .  .  .  $5.00 

VILLE. — On  Artificial  Manures  : 

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A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VILLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 
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VILLE. — The  School  of  Chemical  Manures  : 
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and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
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WAHNSCHAFFE.— A  Guide  to  the  Scientific  Examinatioa 

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WALL. — Practical  Graining  : 

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Interior  Finishing.  By  WILLIAM  E.  WALL.  8vo.  .  #2.50 

WALTON.— Coal-Mining  Described  and  Illustrated: 
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?VARE.—  The  Sugar  Beet. 

Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varietift 
of  the  Sugar  Beet,  Examination,  Soils,  Tillage,  Seeds  and  Sowing 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserva 
tion,  Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWIJ 
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WARN.—  The  Sheet-Metal  Worker's  Instructor: 

For  Zinc,  Sheet-Iron,  Copper,  and  Tin-Plate  Workers,  etc.  Contain- 
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Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin-  Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  -.  $3.00 

WARNER.  —  New  Theorems,  Tables,  and  Diagrams,  for  the 
Computation  of  Earth-work  : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profes. 
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tical Treatise;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix, 
Containing  Notes  to  the  Rules  and  Examples  of  Part  I.;  Explana- 
tions of  the  Construction  of  Scales,  Tables,  and  Diagrams,  and  a 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights 
By  JOHN  WARNER,  A.  M.,  Mining  and  Mechanical  Engineer.  Illus- 
trated by  14  Plates.  8vo  .......  $4.00 

WILSON.  —  Carpentry  and  Joinery: 

By  JOHN  WILSON,  Lecturer  on  Building  Construction,  Carpentry  and 
Joinery,  etc.,  in  the  Manchester  Technical  School.  Third  Edition, 
with  65  full  page  plates,  in  flexible  cover,  oblong  .  .  .go 

WATSON.—  A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds, 
Ivory,  Bone  and  Precious  Woods;  Dyeing,  Coloring,  and  French 
Polishing;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  By 
EGBERT  P.  WATSON,  Author  of  "  The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON.—  The  Modern  Practice  of  American  Machinists  and 

Engineers 

Including  the  Construction,  Application,  and  Use  of  Drills,  LaOie 
Tools,  Cutters  for  Borir.g  Cylinders,  and  Hollow-work  generally,  with 
the  most  Economical  Speed  for  the  same;  the  Results  verified  bj 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  Floor.  Togethei 


HENRY   CAREY   BAIRD   &   CO.'S   CATALOGUE.         29 


with  Workshop  Management,  Economy  of  Manufacture,  the  Steam 
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Illustra  ed  by  eighty-six  engravings.  I2mo.  .  .  .  $2.50 

WATT.— The  Art  of  Soap  Making  : 

A  Practical  Hand-Book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.  Fifth  Edition,  Revised,  to  which  is  added  an 
Appendix  on  Modern  Candle  Making.  By  ALEXANDER  WATT. 
111.  121110 $3.00 

WEATHERLY. — Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
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And  other  processes  for  Confectionery,  etc.,  in  which  are  explained, 
in  an  easy  and  familiar  manner,  the  various  Methods  of  Manufactur- 
ing every  Description  of  Raw  and  Refined  Sugar  Goods,  as  sold  by 
Confectioners  and  others.  I2mo.  .....  $1.50 

WILL.— Tables  of  Qualitative  Chemical  Analysis  : 

With  an  Introductory  Chapter  on  the  Course  of  Analysis.  By  Pro- 
fessor HEINRICH  WILL,  of  Giessen,  Germany.  Third  American, 
from  the  eleventh  German  edition.  Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle, 
Pa.  8vo $1.50 

WILLIAMS.— On  Heat  and  Steam  : 

Embracing  New  Views  of  Vaporization,  Condensation  and  Explo- 
sion. By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated.  8vo. 

$2.50 

WILSON. — First  Principles  of  Political  Economy: 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization. 
By  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo.  .......  $1-5° 

WILSON.— The  Practical  Tool-Maker  and  Designer: 

A  Treatise  upon  the  Designing  of  Tools  and  Fixtures  for  Machine 
Tools  and  Metal  Working  Machinery,  Comprising  Modern  Examples 
of  Machines  with  Fundamental  Designs  for  Tools  for  the  Actual  Pro- 
due  ion  of  the  work;  Together  with  Special  Reference  to  a  Set  of 
Tools  for  Machining  the  Various  Parts  of  a  Bicycle.  Illustrated  by 
189  engravings.  1898 $2.50 

CONTENTS  :  Introductory.  Chapter  I.  Modern  Tool  Room  and  Equipment. 
II.  Files,  Their  Use  and  Abuse.  III.  Steel  and  Tempering.  IV.  Making  Jigs. 
V.  Milling  Machine  Hxtures.  VI.  Too's  and  Fixtures  for  Screw  Machines  VII. 
Broaching.  VIII.  Punches  and  Dies  for  Cutting  and  Drop  Press.  IX.  Tools  for 


Hollow- Ware.  X.  Embossing:  Metal,  Coin,  and  Stamped  Sheet-Metal  Orna- 
ments. XI.  Drop  Forging.  XII.  Solid  Drawn  Shells  or  Ferrules;  Cupping  or 
Cutting,  and  Drawing  :  Breaking  Down  Shells.  XIII.  Annealing,  Pickl.ng  and 


Cleaning.  XIV.  Tools  for  Draw  Bench.  XV.  Cutting  and  Assembling  Pieces 
by  Means  of  R;itchet  Dial  Plates  at  One  Operation.  XVI.  The  Header.  XVII. 
Tools  for  Fox  Lathe.  XVIII  Suggestions  for  a  Set  of  Tools  for  Machining  the 
Various  Parts  of  a  Bicycle.  XIX.  The  Plater's  Dynamo.  XX.  Conclusion— 
With  a  Few  Random  Ideas.  Appendix.  Index. 

WOODS. — Compound  Locomotives  : 

By  ARTHUR  TANNATT  WOODS.  Second  edition,  revised  and  enlarged 
by  DAVID  LEONARD  BARNES,  A  M.,  C.  E.  8vo.  330  pp.  $300 


30        HENRY   CAREY   BAIRD   &   CO.'S  CATALOGUE. 


WOHLER.— A  Hand-Bookof  Mineral  Analysis: 

By  F.  WOHLER,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen.  Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated. 
I2mo.  ..........  $2.50 

WORSSAM.— On  Mechanical  Saws: 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  $1.50 

RECENT   ADDITIONS. 

BRANNT. — Varnishes,  Lacquers,  Printing  Inks  and  Sealing -^ 
Waxes : 

Their  Raw  Materials  and  their  Manufacture,  to  which  is  added  the 
Art  of  Varnishing  and  Lacquering,  including  the  Preparation  of  Put- 
ties and  of  Stains  for  Wood,  Ivory,  Bone,  Horn,  and  Leather.      By 
WILLIAM  T.  BRANNT.     Illustrated   by  39  Engravings,  338  pages. 
I2mo.       .         .         .         .         .         .         .         .         .         .         $3.00 

BRANNT — The  Practical  Scourer  and  Garment  Dyer: 

Comprising  Dry  or  Chemical  Cleaning;  the  Art  of  Removing  Stains; 
Fine  Washing;  Bleaching  and  Dyeing  of  Straw  Hnts,  Gloves,  and 
Feathers  of  all  kinds;  Dyeing  ot  Worn  Clothes  of  all  fabrics,  in- 
cluding Mixed  Goods,  by  One  Dip;  and  the  Manufacture  of  Soaps 
and  Fluids  for  Cleansing  Purposes.  Edited  by  WILLIAM  T.  BRANNT, 
Editor  of  "The  Techno-Chemical  Receipt  Book."  Illustrated. 
203  pages.  I2mo.  .....  .  $2.00 

BRANNT.— Petroleum . 

its  History,  Origin,  Occurrence,  Production,  Physical  and  Chemical 
Constitution,  Technology,  Examination  and  Usesj  Together  with 
the  Occurrence  and  Uses  of  Natural  Gas.  Edited  chiefly  from  the 
German  of  Prof.  Hans  Hoefer  and  Dr.  Alexander  Veith,  by  WM. 
T.  BRANNT.  Illustrated  by  3  Plates  and  284  Engravings.  743  pp. 
8vo.  #7.50 

BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Vine- 
gar and  Acetates,  Cider,  and  Fruit- Wines  : 

Preservation  of  Fruits  nnd  Vegetables  by  Canning  and  Evaporation; 
Preparation  of  Fruit-Butters,  Jellies,  Marmalades,  Catchups,  Pickles, 
Mustards,  etc.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated  by  79  Engravings.  479  pp.  8vo,  $6.00 

BRANNT.— The  Metal  Worker's    Handy-Book   of  Receipts 

and  Processes : 

Being  a  Collection  of  Cl'emical  Formulas  and  Practical  Manipula- 
tions for  the  working  of  all  Metals;  including  the  Decoration  and 
Beautifying  of  Articles  Manufactured  therefrom,  as  well  as  their 
Preservation.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  illustrated.  I2mo.  $2.$c 


HEJM*Y  CAREY   BAiRD   &  CO.'S  CATALOGUE.       3r 

DEITE.— P.  Practical  Treatise   on   the  Manufacture  cf  Per- 

luoiery. 

Comprising  directions  for  making  all  kinds  of  Perfumes,  Sachet 
Powders,  Fumigating  Materials,  Dentifrices,  Cosmetics,  etc.,  with  a 
full  account  of  the  Volatile  Oils,  Balsams,  Resins,  and  other  Natural 
and  Artificial  Perfume-substances,  including  the  Manufacture  of 
Fruit  Ethers,  and  tests  of  their  purity.  By  Dr.  C.  DEITE,  assisted 
by  L.  BORCHERT,  F.  EICHBAUM,  E.  KUGLER,  H.  TOEFFNER,  and 
other  experts.  From  the  German,  by  WM.  T.  BRANNT.  28  Engrav- 
ings. 358  pages.  8vo.  .  ...  .  .  $3.00 

.JD  WARDS. — American    Marine   Engineer,    Theoretical   ana 

Practical  : 

With  Examples  of  the  latest  and  most  approved  American  Practice. 
By  EMORY  EDWARDS.  85  illustrations.  I2mo.  .  .  $2.50 

EDWARDS. — 900    Examination   Questions  and   Answers: 

For  Engineers  and   Firemen   (Land  and  Marine)  who  desire  to  ob- 
tain a  United   States  Government  or  State  License.     Pocket-book 
form,  gilt  edge          ........         $i-5° 

KIRK. — The  Cupola  Furnace: 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foun- 
dry Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter, 
author  of  "The  Founding  of  Metals."  Illustrated  by  80  Engravings. 
8vo.  (1899)  $3-50 

POSSELT. — The  Jacquard  Machine  Analysed  and  Explained: 

With  an  Appendix  on  the  Preparation  of  Jacquard  Cards,  and 
Practical  Hints  to  Learners  of  Jacquard  Designing.  By  E.  A. 
POSSELT.  With  230  illustrations  and  numerous  diagrams.  127  pp. 
4t« #3-00 

POSSELT. — The  Structure  of  Fibres,  Yarns  and  Fabrics: 
Being  a  Practical  Treatise  for  the  Use  of  all  Persons  Employed  in 
the  Manufacture  of  Textile  Fabrics,  containing  a  Description  of  tl.u 
Growth  and  Manipulation  of  Cotton,  Wool,  Worsted,  Silk  Flax, 
Jute,  Ramie,  China  Grass  and  Hemp,  and  Dealing  with  all  Manu- 
facturers' Calculations  for  Every  Class  of  Material,  also  Giving 
Minute  Details  for  the  Structure  of  all  kinds  of  Textile  Fabrics,  and 
an  Appendix  of  Arithmet'c.  specially  adapted  for  Textile  Purposes. 
By  E.  A.  POSSELT.  Over  400  Illustrations,  quarto.  .  $5.00 

&ICH. — Artistic  Horse-Shoeing: 

A  Practical  and  Scientific  Treatise,  giving  Improved  Methods  of 
Shoeing,  with  Special  Directions  for  Shaping  Shoes  to  Cure  Different 
Diseases  of  the  Foot,  and  for  the  Correction  of  Faulty  Action  in 
Trotters.  By  GEORGE  E.  RICH.  62  Illustrations.  153  pages 
I2mcx jgi.oo 


32       HENRY   CAREY   BAIRD   &  CO.'S   CATALOGUE. 

RICHARDSON.— Practical  Blacksmithing : 

A  Collection  of  Articles  Contributed  at  Different  Times  by  Skilled 
Workmen  to  the  columns  of  "  The  Blacksmith  and  Wheelwright," 
and  Covering  nearly  the  Whole  Range  of  Blacksmithing,  from  the 
Simplest  Job  of  Work  to  some  of  the  Most  Complex  Forgings. 
Compiled  and  Edited  by  M.  T.  RICHARDSON. 

Vol.1.  210  Illustrations.  224  pages.  I2mo.  .  .  $1.00 
Vol.  IT.  230  Illustrations.  262  pages.  I2mo.  .  .  $1.00 
Vol.  III.  390  Illustrations.  307  pages.  I2mo.  .  .  $1.00 
Vol.  IV.  226  Illustrations.  276  pages.  I2mo.  .  .  $1.00 

RICHARDSON— The  Practical  Horseshoer: 
Being  a  Collection  of  Articles  on  Horseshoeing  in  all  its  Branches 
which  have  appeared  from  time  to  time  in  the  columns  of  "  '!  he 
Blacksmith  and  Wheelwright,"  etc.     Compiled  and  edited  by  M.  T. 
RICHARDSON.     174  illustrations $i.oa 

ROPER. — Instructions    and    Suggestions    for   Engineers   and 

Firemen : 
By  STEPHEN   ROPER,   Engineer.     i8mo.     Morocco        .        $2.00 

ROPER. — The  Steam  Boiler:  Its  Care  and  Management: 
By  STEPHEN  ROPER,  Engineer.     I2mo.,  tuck,  gilt  edges.         $2.00 

ROPER. — The  Young  Engineer's  Own  Book: 
Containing  an  Explanation  of  the  Principle  and  Theories  on  which 
the  Steam  Engine  as  a  Prime  Mover  is  Based.     By  STEPHEN  ROPER, 
Engineer.     160  illustrations,  363  pages.     i8mo.,  tuck       .          $2.50 

ROSE. — Modern  Steam -Engines  : 

An  Elementary  Treatise  upon  the  Steam-Engine,  written  in  Plain 
language ;  for  Use  in  the  Workshop  as  well  as  in  the  Drawing  Office. 
Giving  Full  Explanations  of  the  Construction  of  Modern  Steairw 
Engines:  Including  Diagrams  showing  their  Actual  operation.  To- 
gether with  Complete  but  Simple  Explanations  of  the  operations  of 
Various  Kinds  of  Valves,  Valve  Motions,  and  Link  Motions,  etc., 
thereby  Enabling  the  Ordinary  Engineer  to  clearly  Understand  the 
Principles  Involved  in  their  Construction  and  Use,  and  to  Plot  out 
their  Movements  upon  the  Drawing  Board.  By  JOSHUA  ROSE.  M.  E. 
Illustrated  by  422  engravings.  Revised.  358  pp.  .  .  $6.00 

ROSE.— Steam  Boilers: 

A  Practical  Treatise  on  Boiler  Construction  and  Examination,  for  the 
Use  of  Practical  Boiler  Makers,  Boiler  Users,  and  Inspectors;  and 
embracing  in  plain  figures  all  the  calculations  necessary  in  Designing 
or  Classifying  Steam  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  73  engravings.  250  pages.  8vo #2.50 

SCHRIBER. — The  Complete  Carriage  and  Wagon  Painter: 
A  Concise  Compendium  of  the  Art  of  Painting  Carriages,  Wagons, 
and  Sleighs,  embracing  Full  Directions  in  all  the  Various  Branches, 
including  Lettering,  Scrolling,  Ornamenting,  Striping,  Varnishing, 
and  Coloring,  with  numerous  Recipes  for  Mixing  Colors.  73  Illus- 
trations. 177  pp.  I2mo.  ...... 


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